Tony Fitzpatrick's life has been blighted by tragedy.

His brother, Paul, died at the age of 32 of dermatomyositis, a rare and ravaging disease which attacks the skin and muscles. His mother died at the age of 60 - and on her birthday - from lung-cancer. But his worst - and yet most inspiring - tragedy was the death of Fitzpatrick's little boy, Tony junior, at the age of six.

Fitzpatrick, a former St Mirren captain and manager, has written a children's book which is both a dreamy, colourful adventure as well as an elegiac love-letter to the son he lost 32 years ago. "The Promise - Together Again" is a mesmerising adventure telling the story of Saber, a sad bear, being re-united beyond a magical rainbow with Theo, his dead son. In the story the coming together is made possible by the irrepressible Babakoochi Bear.

"Virtually from the day he was born that was my nickname for my wee boy - 'Babakoochi'," says Fitzpatrick of Tony junior. "I don't know where the name came from, it just sprang into my head. Tony was small and hairy - a bit like me - and so he became 'Babakoochi Bear'. He loved the name."

Father and son spent just six and half years together. Fitzpatrick had been building a football career of some promise, leaving St Mirren to sign for Bristol City in 1979, and being selected for Scotland squads under Jock Stein, when his life began to fracture. Tony junior turned four in 1981: the start of two years of pain and, ultimately, bereavement.

"When my son first took ill we didn't know what it was," says Fitzpatrick. "He would get very tired, very warm, and my wife, Elizabeth, and I knew that something was wrong. At first the doctors told us he had a virus, and that we should give him medicine, so we did.

"But then it got much worse. One day I came home from training and Elizabeth said to me, 'I'm worried, he's having a very bad time.' Wee Tony started coming out in purple spots, and a doctor insisted we take him straight to the hospital. Once there he was found to have septicemia and meningitis and we were told it was life-threatening, it was very, very serious."

Tony junior was finally diagnosed with acute myeloid leukemia, an uncommon cancer among children, and his parents were told that there was little hope.

"They said to us, 'he's got acute myeloid leukemia - there is nothing we can do.' I was told my son might die very soon. In fact, by some miracle, there was two years between Tony first being diagnosed and dying, and of those two years, we had him at home for just three months. My wife and I took in turns to stay over at the hospital."

Fitzpatrick well remembers those painful days when he tried to keep his football career on track - he was 24 - while coping with the slow, inexorable death of his little boy. And Tony junior, he says, even as a lad of six, had a sense of what might await him.

"He knew what was happening," says Fitzpatrick. "He heard things all the time. He was surrounded by sick children and, one by one, many of them died. He'd hear nurses talking and he'd see things. There was a wee girl in the ward that he got friendly with, and one minute she was there, and the next she wasn't. At one stage almost every child in that ward in Yorkhill died. So Tony, even at six, had that sense of what death and dying were about.

"One day, seeing another kid's empty bed, he said to me, 'Dad, I don't want that to happen to me.' I told him not to worry, that he was going to be okay. What else could I say to my son? But, to be honest, I think he knew. For two years his world was that ward, and he saw and heard everything."

After two gruelling years of treatment, discomfort, fear and unknowing, Tony Fitzpatrick junior finally died on January 9 1983. His parents had been with him through the night before their final moments together.

"On that final evening he was very poorly. I'd gone downstairs for a cup of tea and the nurse came down and said to me, 'you'd better come up'. When I got to Tony's bed I just said to my son gently, 'everything is okay...how are you feeling?' He looked up at me, then closed his eyes, and slipped away in the hours ahead."

When Fitzpatrick and his wife left Yorkhill Hospital that morning, something occurred which, even after a gestation period of 32 years, would inspire him to write his book.

"I'll never forget that morning. Tony died at 6am and my wife and I had to get a lift down from the ward to the ground floor. Our son had just died, and people were coming in and out of that lift, laughing and joking and chatting away. It was very surreal. I wanted to say to them, 'hey, d'you know what's just happened?'

"We stepped out from the hospital, with the sun coming up. It had been raining and there was this incredible rainbow in the sky. I stopped and looked at it for ages and, while there was all this pain, I suddenly felt a peace from somewhere. I looked at that rainbow and thought: 'That's it. That's Tony. He's at peace now, he's okay.'"

Life somehow moved on. Fitzpatrick was just 16 when he got married, and he and his wife went on to have three more children, and somehow found happiness again. But his football career didn't blossom as it might have.

"My son dying took that hunger and desire away from me," he says. "I just didn't have the same appetite for football any more. I'd stayed many nights in a hospital and I'd lost my son. Looking back I now wonder how I ever managed to keep playing at all.

"Tony's death taught me a lot of things - one of them being to stop being so selfish. I'm ashamed to say it now but, back when I was young, I put my football career ahead of my family and friends. But my son's death changed all of that. I realised that family - and faith too - was far more important than football."

With his book having been written, Fitzpatrick says he sometimes dreams of Tony junior, and of what his life might have been like. He would have been 39 years old today.

"My marriage to Elizabeth eventually failed after 20-plus years, but after Tony's death, yes, we did find happiness again with our other children. You have to move on. I had to take on a responsibility I had never known before, and time does heal. But I've never, ever forgotten the little boy we lost.

"Tony junior would have been 39 now, and I often imagine what he'd be like today. I used to see kids who were eight or nine, or older kids at 15 or 16, and think, 'maybe Tony would look like that kid over there.' I've pictured him and imagined him at various stages of the life he might have had. I loved him so much."

*The Promise - Together Again by Tony Fitzpatrick. Find it at www.babakoochibear.com. Book signings at Waterstones Braehead this Saturday, 2pm.