Andrew Kornberg, director of the neurology department at the Royal Children's Hospital, called Jack's recovery miraculous, and the Vatican agreed - not for the MS or cancer but for the unprecedented recovery of his intellectual capacity. The story of the Woodend identical twin has not been told until now because, while the cases were being investigated by the Vatican, the family was asked to keep it secret. It was presented to Pope Benedict last year, along with Kathleen Evans's cure from inoperable brain and lung cancer - the case chosen as the second miracle. The Simpson family's ordeal began in 1999 when Jack, then eight, collapsed at school. ''At first we thought he'd hit his head. His eyes were rolling, he couldn't stand and had no comprehension. It was unbelievably horrible,'' Mrs Simpson said yesterday. For the first year there was no diagnosis, as his central nervous system went into meltdown, leaving him paralysed. Soon after the problem was revealed as juvenile MS - with a maximum life expectancy of five years - the family noticed lumps the size of bars of soap in his neck and groin.

''When he went to the nuclear medicine department and they put the tracer in, he was lit up like a Christmas tree. It was quite advanced, stage four Hodgkin's lymphoma.'' A friend organised novenas (nine-day prayer cycles) to Mary MacKillop at St Ambrose's Catholic Church at Woodend in 1999 and 2000, but nothing changed at first. For Mrs Simpson the turning point came one night in 2000. ''That night I thought Jack was going to die. He seemed to be in the last stage, with the breath rattling. I thought, 'You can't keep fighting forever, you have to surrender,' and I said, 'If you want him, God, you can have him.' '' But in the morning he was still alive. She thought he might be cured, so she stood him up, but he was still paralysed.

''That's when Mary MacKillop appeared. She helped me lift him up and get him back into bed. From then on, I knew I was never alone and her strength became mine.'' Jack started improving. One day in 2004, at a routine cognitive assessment at the Children's, Mrs Simpson was greeted by a doctor telling her something wonderful had happened. ''The MS was gone, the cancer was gone, the epilepsy controlled - he now suffers about one episode a year - and his cognitive faculties were returning.'' Mrs Simpson wrote her account that year, and it was given to Sister Maria Casey, who was in charge of presenting the case in Rome for Mary MacKillop to be made a saint. ''She rang me, and the Vatican doctors came out from London to interview Dr Kornberg. The miracle she presented was the return of his intellectual competency, because that has never been documented in human history.''

In April 2005, Professor Kornberg wrote a letter on the family's behalf, saying: ''Jack's recovery has been miraculous … On a personal level I wonder whether there was something special happening here … I will always look back at Jack's case and remember that one should never lose hope.'' Yesterday he confirmed his view that Jack had recovered miraculously. ''Sometimes you just can't explain it,'' he said. Jack, who finished year 12 last year and now works part-time at Coles, does not remember much of his illness, but said yesterday: ''It just felt like I was on fire.'' Now he feels fine, and says he is really excited about going to Rome. Mrs Simpson says: ''It's a beautiful story, the kind of story that gives hope to people. It could so easily not have had a happy ending.''