Luigi Costa, 72, was sentenced to 16 years behind bars for the bizarre attack which left Mr Freebody, his neighbour, dead on the dining room floor of his multimillion-dollar Red Hill home in July 2012.

An eight-year non-parole period means Costa will be eligible for release by July 2020, and will potentially live out his remaining years in the community.

The sentence, and in particular the low non-parole period, has angered the Freebody family, who made a brief statement outside court.

"We are incredibly disappointed with the result, especially regarding the non-parole period of eight years," Mr Freebody's son, Brett, said.

"[It's] very distressing, and that's all I've got to say at this point."

Mr Freebody was a well-known figure in the Canberra community, particularly in Queanbeyan, building a successful business empire, and becoming a local sporting legend in rugby league and cricket.

He served in World War II, and was greatly affected by his time in Borneo, where he helped find and rescue former prisoners who had survived the Japanese Sandakan death marches.

Costa, a wealthy property owner, had invited Mr Freebody and his wife over for dinner and drinks on July 22, 2012, to thank them for looking after his Mugga Way home.

The two men, who had little to do with each other before that night, consumed significant amounts of alcohol.

Lennis Freebody, Mr Freebody's wife, left due to Costa's increasingly foul language.

Within three minutes, Costa made a call to a friend, leaving a message for him to call the police to his home.

Costa then dialled triple-0 himself, saying he had been attacked, and asking for police to come. Moaning could be heard in the background, likely due to the cracked vertebrae Mr Freebody had suffered from a fall or a push.

After he made the call, Costa took a knife to Mr Freebody, inflicting a series of stab wounds and cuts to his neck, face, chest, stomach, and genitals. Mr Freebody was dead by the time police arrived.

Costa fought the murder charge in an ACT Supreme Court trial, claiming mental impairment, but a jury found him guilty earlier this year.

Chief Justice Helen Murrell on Thursday sentenced Costa to 16 years behind bars, with a non-parole period of eight years.

She said the crime was not in the worst category of murder.

"The offence was perpetrated against a vulnerable victim and it involved a frenzied and multi-faceted attack.

"However, I do not accept the Crown submission that the offence is in the worst category of murder offences."

"The attack was spontaneous and unplanned. The murder weapon was obtained at the last moment."

The crucial issue for the jury in deciding Costa's guilt was whether, once his drunkenness was disregarded, dementia made him unable to recognise the wrongfulness of his actions, or unknowing of the nature and quality of his conduct.

Costa had acted bizarrely on the night, calling police while committing the crime, breaking out into song in police's presence, expressing affection for an arresting officer, and quickly turning aggressive and abusive.

The jury's task was complicated by Costa's state of intoxication and its disinhibiting effect on him. He gave a blood alcohol reading of 0.157grams, about three times the legal driving limit.

During sentencing, Chief Justice Murrell was also asked to consider his cognitive impairment, and whether it reduced his moral culpability for the crimes, or made him less suitable as a vehicle to deter others in the community from committing such offences.

She found that he did suffer from a mild form of dementia, which was probably the result of long-term alcohol abuse.

Chief Justice Murrell said the killing simply would not have happened if Costa had not been drunk.

"Nevertheless, the offender's mental impairment did play a role in the commission of the offence," she said.

"It meant that the offender's mental state was more vulnerable to the impact of the excessive consumption of alcohol."