Mrs Thomas told the Special Commission of Inquiry into Acute Care at John Hunter Hospital yesterday that she believed his death could have been prevented.

She said she wanted her son's death investigated, particularly whether doctors at John Hunter Hospital treated him properly and transferred him to Royal North Shore neurosurgeons in adequate time.

"A neurosurgeon at Royal North Shore who operated on Peter told us that if Peter had been taken to Sydney earlier he would have had a better chance of survival," Mrs Thomas said, sobbing.

"Peter's doctor, Dr Fluitt, has told me that Peter should not have died. He told me to see a lawyer.

"Our lawyer has told us that she has seen studies of patients who have venous thrombosis with ulcerative colitis and that it is treatable and that death occurs rarely in one in 10."

Mr Thomas was diagnosed with ulcerative colitis four years ago and attended John Hunter Hospital on February 26 with bad diarrhoea.

On February 29, he was diagnosed with cerebral venous thrombosis after he could not move his right arm or leg.Doctors told him it was a rare but treatable complication of ulcerative colitis.

The next day the father of two was moved to the intensive care unit and at lunchtime his family was told he would need to be transferred urgently to Royal North Shore Hospital's neurosurgical unit.

"The doctors kept changing their minds about how he was to be transported to the Royal North Shore, first it was by road ambulance and then by helicopter," Mrs Thomas said.

He was transferred by helicopter at 6.30pm.

After brain surgery at Royal North Shore Hospital, he was put on a life-support machine, which was turned off on Monday, March 3.

"We were told that Peter was very, very ill and that when they had operated they had never seen anything like Peter's brain," Mrs Thomas said.

Commissioner Peter Garling, SC, said he would refer the matter, like all others raised in the inquiry, to the Health Care Complaints Commission.

A Hunter New England Health spokeswoman said the hospital became aware of the family's concerns only at the inquiry and it would conduct an internal investigation.