Father of two Tom Biviano, 39, suffered severe head injuries after the young men he had tried to pull apart in a Maitland street brawl early on Saturday turned on him.

In a callous act, the warring parties resumed their fight as he lay lapsing into a coma.

"It is a matter of life and death at the moment, we are just living hour by hour," Mrs Young said. "We are still hanging in for him."

Mr Biviano had been out on the town with a mate when they came across two groups of young men fighting near the intersection of Ken Tubman Drive and Bulwer Street about 2.50am.

But the "big kitten's" instincts in pulling the brawlers apart may have cost him his life, when one of the men hit him from behind.

"If he thought your life was being threatened he would be thinking of you, not himself," Mrs Young said.

"He's not a violent person at all and he's got a good heart. Everybody that knows him tells me what a good son I've got."

His devastated family remains hopeful the plasterer can awake from the drug-induced coma he was placed in after being rushed to John Hunter Hospital's intensive care unit.

Mrs Young has kept a vigil by her son's bedside for the past two days, and photographed him in his hospital bed yesterday.

"I'm going to show [the photographs] to him when he gets out," she said. "I'm going to say to him, you're the reason my hair's going grey at the sides."

He was last night listed in a critical condition.

Mrs Young said Mr Biviano loved his two girls, Savannah, 13, and Tiarne, 11, who live with their mother.

He is a big Western Bulldogs fan in the AFL, and played Australian rules football with the Cardiff Hawks for several years.

Detectives are still hunting the main attacker and believe there were several people who left a nearby licensed premises just before the callous attack who may be able to help the investigation.

Mrs Young echoed their calls.

"If someone can be jolted to think that there's a bit of information that can solve this, please come forward," she said.

Information can be forwarded to Central Hunter detectives on 4934 0200 or Crime Stoppers on 1800 333 000.