If you live near Lunenburg, Massachusetts, in northern Worcester County, you might have seen us at the puppet show: a greying, self-conscious woman and her giggly adult child. About once a month, when the Drawbridge Puppet Theater changes its show – from Jack and the Beanstalk to The Frog Prince to Rumpelstiltskin and so on – my 26-year-old son and I make the ten-mile drive along the winding back roads from our home to attend a performance. Mindful of obstructing the view of the toddlers and preschoolers who come with their parents, we always sit in the back row. And yet we can’t hide: the child with the three-day whiskers who claps loudly for all the puppets attracts wondering stares from the Baby Gap crowd.

As we wait for the curtain to part in the middle of the cardboard castle, where fuchsia morning glories climb the pink brick walls, Randy babbles to himself in his sing-song, repeating words and phrases that have nothing to do with the show. Sometimes he presses one hand to an ear, as though he is receiving messages. More for my sake than anyone else’s – this place is full of babies and little kids and is highly Randy-friendly – I tell him to keep his voice down. ‘Keep your voice down,’ Randy echoes.

At curtain time Mr Paul walks in front of the stage. He tells the children about today’s show, involving them with easy questions. ‘How many stepsisters does Cinderella have?’ ‘Is there a witch in this story?’ Little hands shoot up; children call out answers. ‘Yeessss!’ says a loud voice from the back of the room. ‘Excellent, Randy,’ Mr Paul acknowledges with a kind smile. Heads swivel toward us.

Mr Paul explains the difference between puppets and marionettes, and tells us which to expect in today’s show. In his gentle, Mr Rogers-like way, he reminds us that the show is only make-believe: there is nothing to be afraid of. ‘Clap, laugh, and don’t be afraid,’ he says.

‘No, we hope not,’ says Randy in a solemn, low voice.

Looking back at Randy during the first performance we attended six years ago, I see no trace of the traumatic year he had just lived through. On the contrary, he was excited about his birthday that summer and winning the rights and privileges his sister now enjoyed. Though he seemed to accept that he wouldn’t be driving a car or following Allie to college, he understood the truly important thing about turning twenty-one. ‘Be a man soon,’ he said in his loud, Jerry Lewis voice. ‘Drink lots of beer, wine, Chardonnay and champagne.’

From the moment the puppets bounced onto the stage – big, odd, dimensional – Randy had been transformed. His babbling ceased. His face, so often distorted by autism’s siren song, became the handsome face it should have been. The face I had often looked on while Randy was sleeping. The face that had turned girls’ heads until they realized something was wrong with him. Here in the puppet theatre Randy was fully present: not as a twenty-year-old man, but as a normal boy of three or four, who still believed in magic. He smiled; his lovely grey-blue eyes danced. In this theatre of make-believe, Randy became a real boy.

This is the story of our last six years – years that Randy, a human calculator, may some day include in his tally of the last years Mummy was alive, the last time I took him to the puppet show. ‘A Sunday,’ he will note. It is the tale of how an autistic boy became a man, what he lost along the way, and what adulthood now means for him and his ageing parents, who live together in a pumpkin-red colonial set in a forest of wetlands.

Though Randy has never forgotten our first house – ‘Don’t have to forget it,’ he says excitedly – or the day we finally sold it (‘on September 28, 2002, a Saturday’) after six years of renting it out – his sense of home is fixed. We moved from our house on Boston’s South Shore to our home north-west of Boston ‘on June 26, 1996, a Wednesday, before we sold the old house’, Randy says. In the framed watercolour Randy painted for an elementary-school assignment, the red house has purple windows, a purple roof and a block of dark turquoise in the red-brick walkway. A light green starburst alongside the chimney connotes the hemlocks rising around us; in the attached two-car garage is the suggestion of a heart. The downstairs glows in yellow lamplight.

Now picture another house. It is a ranch, with a carport instead of a garage – and it is actually two houses, with a family living in each half – exactly like all the other houses on the army base at Fort Rucker, Alabama. Colour it drab brown. The year is 1961. Here I lived with my mother, my father, my younger brother, Johnny, and our dog, a boxer we named Bama for Alabama.

In my bedroom at the back of the house I sometimes had tea parties with Bama, who allowed me to dress her in my baby clothes and paint her toenails red with Mama’s polish. Though she was full-grown, she sat on one of the child’s chairs at the little table – at least to a point. ‘Pat, I just saw Bama running down the street in a dress and bonnet,’ a neighbour told my mother on the phone. ‘Yes,’ Mama said with a laugh. ‘Linda’s been having a tea party.’

But now the house is dark. The only light source is the headlamp on the helmet of an army MP patrolling the premises all through the night.

Though we hadn’t lived there long – as an army family, we were always moving – I remember being happy. There were afternoons at the lake, picnicking and waterskiing and riding in the boat we shared with another army family. And Daddy was not only the handsomest man in the world (in his white dress uniform, he looked just like a prince); he made me feel very loved. That my mother was also glamorous and a beauty – an Elizabeth Taylor type with dark hair, red lipstick and tinkling gold-coin jewellery – is not significant. She is there and yet curiously absent in my memories of this time. It was Daddy who made life magical. Daddy who got down on the floor and played with us and gave us piggyback rides. He himself was ‘a big kid’, said Mama. He taught me how to swim. After dinner, he sat next to me at the linoleum kitchen table, helping me with my arithmetic homework, which was painfully hard for me. He spent months working on a Christmas present for Johnny: a big board on which an electric train wound through villages dotted with bright red and yellow trees dressed in New England fall foliage, unlike the trees in Alabama. The time I was miserably confined to bed with the chickenpox, Daddy entered my darkened bedroom and put the warm puppy who was Bama on my bed – an early Christmas surprise.

I was Daddy’s girl. And he never just stood or sat next to me; he encircled me. With his big arms wrapped around me, cuddling me, I felt special and safe. There was no reason to be afraid.

And yet in the week running up to 5 March 1961, I found myself thinking terrible thoughts. I imagined that one of my parents would die. The idea came to me after my close girlfriend on the base hurt my feelings. I thought about my parents dying and then wouldn’t she be sorry she had said such a thing. But the thought of Daddy dying made me flinch inside, as though someone had hit me.

It was Saturday night and my parents were having a party. There was nothing unusual about that. They often barbecued and danced to records on the patio behind my room.

As wonderful as Daddy was, he was also a tease, and I was overly sensitive and easily hurt. And so when at the party Daddy teased me about something, then waited for his goodnight kiss, I made a point of kissing one of the other officers goodnight instead of him, then flounced off to bed. Daddy laughed.

I woke the next morning in the dark to the smell of smoke and the sound of my parents shouting at me to stay in my room and not open the door: Daddy would come and get me. The house was on fire. My bedroom was down the hall from my parents’ bedroom and Johnny’s.

After Captain Harbert across the street came to my window and pulled me out of the room, I waited and worried about Bama. Mama and Johnny were at the Boyles’ house next door to our house; I was across the street with the Harberts and their daughters. My dog, my dog, I kept worrying aloud. Where’s my dog? I have no recollection of the moment, but I learned later that Mrs Harbert came into the bedroom where I was waiting and told me that my father had died in the fire, and Bama had died too. (‘Not my father,’ I said.) I do recall standing in their carport, wrapped in the sheltering arms of Captain and Mrs Harbert, and watching the firemen carry a covered stretcher out of our burned and gutted house, then lift it up into the ambulance and out of sight. By then, I knew about Daddy and Bama, but I was confused: surely whatever was under that lumpy, shallow blanket could not be my big father. And where was the stretcher for my dog?

Back home in Portland, Oregon, I was sitting in a chair in my grandparents’ familiar, cluttered apartment – my family’s second home during our first years when Daddy had been in Korea – when I finally and forever understood how Daddy died. Years later, my mother said that she had been keeping the newspapers from me and instructing everyone to do the same. But now Grams, Daddy’s mother, to whom I had always been close, though not as close as I was to my grandfather, dropped the newspaper article with my father’s picture in my lap. The formal portrait of Daddy in his uniform was the same picture my grandparents kept in a big frame in their living room, along with several others of Daddy and Johnny and me. Daddy was their only child. After the fire I realized that now they had only Johnny and me. The article in the Oregonian said that Lt Davis was attempting to rescue his daughter, Linda, when he was overcome by the flames and died.

And so it was all my fault.

Daddy was twenty-nine when he died. I was eight, and I knew, as each remaining strand of my world unravelled, falling in charred black wisps in the little room around me, that my life would never, ever be the same.

Even after I was married, at the age of twenty-eight, I vacillated about having children. I worried about being a good mother, worried that Chuck or I would die, leaving our children. But as my third year of marriage approached I wanted a baby, and in 1984, at age thirty-one, two years older than my father had been when he died, I gave birth to a perfect and beautiful daughter, whom we named Alexandra and called Allie. I felt strongly about having two children, not one, as my Davis grandparents had, and having them close enough in age so that they could play together, as Johnny and I had done. Randy – named Randall Davis Yanikoski for my father, John Randall Davis, who had also been called Randy – arrived less than two years after his sister. He too seemed perfect.

Like all autistic children, Randy claimed more than his fair share of his mother’s attention. Allie, who had enjoyed my full consideration for her first two years of life, felt angry and resentful.

A series of snapshots from those early years: Randy in his later infancy, a papoose on my back as I wash dishes, fold laundry and walk around the house – a strategy to keep him from crying. Movement calmed him by addressing the sensory deficit so common in autism, but the golden-curled, two-year-old Allie, gripping a stuffed polar bear under one arm and a buffalo under the other, would not have understood that. There were the months before Randy started school at age three, when my racing him in and out of Boston for an early language class at the Children’s Hospital inevitably led to a day I got stuck in traffic while rushing back to pick Allie up from kindergarten, and found her orphaned on the sidewalk, her grey-blue eyes and rosebud mouth swollen from crying. There was the month I spent toilet-training Randy so that he could go to school in underwear instead of diapers – a twenty-four-hour-a-day campaign. The summer his words began to come and take root – prompted by my carefully detailed pencil sketches of everything in the house he might ask for, from Diet Coke to a fork to his big stuffed brown bear, Felix. My labelled drawings for Randy papered the kitchen cabinets, turning the kitchen into a classroom. Allie, meanwhile, produced a drawing of her own. One day the social worker who was leading a group for elementary-school siblings of disabled children showed me Allie’s crayoned portrait of her family: Papa, Randy and Allie. Mummy was notably absent.