Roughly 18 months ago, 82-year-old war veteran Ian Gore was beaten almost to death after he confronted a young man who was kicking bins on the street outside his Canberra home.

It was late, and the youth, Jacob Seretin, now 22, had drunk half a bottle of rum.

The victim came out, spoke with Seretin, before going inside and returning with a pick handle and a camera.

The younger man jumped on him, causing him to fall back and smash his head on a rock, rendering him unconscious.

Mr Gore remembers regaining consciousness twice.

The first time the younger man had him pinned to the ground. The next he had his hands around his neck, choking him.

The victim was struck repeatedly and forcefully in the head as he lay unconscious.

Photos of his injuries are far too graphic for publication. Even images taken one month after the attack still show the devastating toll it took on his body.

His injuries included fractured facial bones, bruising and bleeding to the brain, injuries to an eye that almost caused blindness, lacerations to the face and scalp, and chipped teeth.

Doctors told him he had a 50:50 chance of surviving. They now say any further injury to his head would be "catastrophic".

Psychologically, the bashing is still a source of major trauma for Mr Gore and his family, who now no longer feel safe in their own home.

The elderly man, who served in Korea, Japan, and Vietnam, now suffers post-traumatic stress disorder, and has trouble with memory, concentration, and understanding words.

"Since the attack our lives have been in turmoil," the victim wrote in a statement.

"No longer are we the masters of our own destiny."

"Our lives have been irrevocably changed, but not for the better."

On Friday, Seretin faced a sentencing hearing in the ACT Supreme Court.

The court heard the attack was extremely unusual and completely out of character for Seretin.

He has a clean record, no real drug and alcohol problems, no mental health issues, and gave no indication of previous violent tendencies.

His own barrister, Alyn Doig, was at a loss to find a reason for the unprovoked attack.

"I shake my head and try to think what on earth I can point to to explain this attack," Mr Doig said.

He said his client had shown remorse, and was a young man who would now live with what he'd done for his whole life.

The barrister said his client offered his unreserved apologies to the victim and his family.

"I know that will be cold comfort, but I specifically sought those instructions and those instructions have been forthcoming," Mr Doig said.

Prosecutor David Swan said the attack was "abhorrent", "sustained", and "prolonged", and targeted a vulnerable victim. Mr Swan said it would have been clear to Seretin that he was attacking an elderly man.

Mr Swan said the only suitable sentence would be one of imprisonment, and urged the judge to consider the impact on the victims, protection of the community, and general and specific deterrence.

Justice John Burns will hand down his decision next week.