The family of a disabled man bashed to death in his Victorian home have called his teen attackers "evil", "animals" and "sadistic thugs".
John Bourke had brittle bone disease, which caused him constant pain, but he loved life, birthdays, Christmas time and his Richmond AFL team.
The 45-year-old died after being bashed by two teens inside his Maryborough home in July 2018.
The boy who inflicted the fatal blows cannot be named because he was 15 years old at the time. He is awaiting sentence after being found guilty by a jury of manslaughter.
His accomplice, who stomped on Mr Bourke but wasn't found to have caused his death, has pleaded guilty to home invasion and recklessly causing serious injury.
The 19-year-old also cannot be named because he too was underage during the attack.
Mr Bourke's heartbroken dad, Peter, told a pre-sentence hearing in Victoria's Supreme Court on Friday his life was now empty.
He didn't understand how "these two animals" and "sadistic thugs" could inflict such violence on a defenceless and disabled man.
"I don't know why John died, but I know why he lived; he was an inspiration to many."
Mr Bourke's sister, Antoinette Blake, cried as she described how her sibling loved his Richmond Tigers, and family Christmases and birthdays.
"He endured so much pain but he rarely complained. He was worried about everyone else," Ms Blake said.
"You only had to look at John to see he couldn't defend himself.
"These boys are evil and my brother is dead."
Prosecutor Grant Hayward said Mr Bourke died in a vigilante attack, after being mistaken for another man thought to have committed a sexual offence.
Mr Bourke was about 145cm tall and couldn't stand without crutches.
His brittle bone disease meant even a bump or knock could cause fractures. He suffered about 400 of these throughout his life.
The teens came to Mr Bourke's house from a nearby party.
The younger boy thought the man was a pedophile but his accomplice later admitted "we got the wrong house".
The elder teen told police he'd drunk about nine Carlton Draft stubbies that night, and said had punched Mr Bourke and stomped on his legs.
"I didn't really wanna to f***ing hurt his head that much. I didn't wanna f***ing kill him," he said, adding he'd ended up trying to stop the attack.
In part of a letter read to the court, his mother said he was devastated Mr Bourke had died "and not a day goes by when he doesn't think of this".
The 19-year-old is expected to face a further pre-sentence hearing on December 4.