The 18-year-old boy convicted of John Bourke's murder was on Tuesday sentenced in the Supreme Court to 14 years' imprisonment.

The teen will spend the first three years of his sentence in a youth justice centre. He will be eligible for parole in nine years.

Mr Bourke's father Peter said he would never be satisfied with the sentence handed down to his son's killer.

"It doesn't matter how long the mongrel got, it's still not enough," he said. "Nothing will bring John back. Things just don't get easier. We just miss him.

"Words can't explain how great he was. He was very thoughtful. He helped others and others helped him. He can never be replaced."

Related news: Teen to avoid adult prison after being found guilty of murder

On July 15, 2018, the then-15-year-old boy and an older teen left a party and went to Mr Bourke's Derby Road home.

The 15-year-old wanted to confront another man who had allegedly sexually assaulted a close friend, but attacked Mr Bourke in a case of mistaken identity.

The younger boy kicked in the front door of Mr Bourke's home and began assaulting him when he came to the door on crutches.

The older boy, then aged 17, punched the 45-year-old twice in the head and stomped on his leg between two and four times.

IN OTHER NEWS

The 15-year-old continued to attack Mr Bourke even after his older friend tried to stop him. The teen stomped on the man's head twice, killing him.

Mr Bourke had osteogenesis imperfecta, or 'brittle bone disease', which left him highly susceptible to fractures.

At the time of his death, Mr Bourke needed crutches to walk and used a mobility scooter.

In her sentencing remarks, Justice Elizabeth Hollingworth described the murder as "cowardly and disgusting".

"It must have been obvious to you, even in your drunken state, that you were attacking a slightly-built, disabled man who was only 133 centimetres tall," the judge said.

"It must also have been obvious that he was utterly defenceless against an attack by two physically fit teenagers.

"You kept going, even as he called out for you to stop the assault."

Justice Hollingworth said it would have been an "absolutely terrifying ordeal" for Mr Bourke, who was an "innocent and defenceless man".

"It is clear that John Bourke was a much-loved son, brother, uncle, and friend, who inspired many with his courage and stoicism," the judge said.

"Even though he endured a life of great pain, Mr Bourke rarely complained, and always looked on the bright side of life."

Justice Hollingworth made note of a photo of Mr Bourke's body that was found on the 18-year-old's phone the day after the murder.

The judge said while it was possible the teen took the photo, she could not be satisfied beyond reasonable doubt that he did.

Justice Hollingworth noted the 18-year-old's history with drug and alcohol addiction, the abuse he experienced and witnessed at the hands of his step-father, and his diagnosis of schizophrenia and post-traumatic stress disorder.

The judge also said his young age was an important factor in sentencing, with his rehabilitation prospects appearing "reasonable".

The 18-year-old boy was sentenced to 14 years' imprisonment with a non-parole period of nine years. His 1066 days in pre-sentence detention were reckoned as already served.

The older boy, now aged 19, was last year sentenced to three years in a youth justice centre after pleading guilty to recklessly causing serious injury and home invasion.

If you are seeing this message you are a loyal digital subscriber to The Courier, as we made this story available only to subscribers. Thank you very much for your support and allowing us to continue telling Ballarat's story. We appreciate your support of journalism in our great city.