Andre Duplin was convicted of attempted murder in November 2018 for what the judge described as a" horrific, life-threatening attack."
The 73-year-old man has been behind bars since the June 7, 2016 incident.
With credit for his pre-sentence custody, he would face a further four years, seven months in jail, assistant Crown attorney David Didiodato said.
Defence lawyer Jennifer Tremblay-Hall argued that her client, who has already served the equivalent of five and half years, should be sentenced to time served, plus a lengthy probation.
A five-to-10-year sentence is the range for this offence and the defence submission would be a fit and just sentence, she said.
Ontario Court Justice Andrew Buttazzoni will give his decision Tuesday.
Larry Paquette was asleep in a recliner in his Rupert Acres Drive home when the man he told the court was his "favourite uncle" attacked him.
Duplin struck the younger man 22 times with the machete, including seven blows to his head that fractured his skull.
Paquette's arms and hands also were injured as he tried to defend himself.
The assault occurred after the two men had spent the day drinking beer and smoking marijuana.
Didiodato cited five aggravating factors in his sentencing submission.
The assault was a completely unprovoked and unexpected attack on a vulnerable victim, he said.
Duplin waited until Paquette was asleep, unable to defend himself or prevent the attack.
The machete was "aimed directly at the head of the victim" and "selected to cause serious bodily harm and it did," the prosecutor said.
He also pointed to the nature of the inflicted injuries which included multiple skull fractures and lacerations, fractured forearms, and severed tendons.
Paquette was airlifted to Toronto and underwent multiple surgeries over the months that followed.
Didiodato also noted that Paquette no longer feels safe in his home or going outside of it, and the injuries have affected his ability to take care of himself.
Tremblay-Hall said there is no evidence of pre-meditation or planning, and after Duplin stopped assaulting his nephew he ran to get help.
"It appears to be an impulsive act," she told Buttazzoni. "He was immediately co-operative with police. The whole act is inexplicable."
The court has to take into account her client's age — he will be 74 in Feburary — and that he suffers from a cognitive impairment, Tremblay-Hall said.
As well, at the time he "was engulfed in the loss of his partner and alcoholism."
Duplin, who has deep remorse, has no record of violence, the defence said.
Even though the attack involved 22 significant strikes, "it was quick," she said. "It wasn't long drawn-out torture."
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