Andre Duplin struck the younger man 22 times with the weapon, inflicting numerous, serious fractures to the victim's skull and injuries to his hands and arms, including a broken arm.
The brutal assault, by his "favourite uncle," occurred June 7, 2016 in Larry Paquette's Rupert Acres Drive home after the pair spent the day drinking beer and smoking weed.
Paquette fell asleep in his recliner while the they were watching television after dinner. The Aweres Township man awoke to Duplin hitting him "really, really hard" with the machete.
Ontario Court Justice Andrew Buttazzoni said Friday that he was satisfied, beyond a reasonable doubt, that the accused intended to kill Paquette.
"The unprovoked attack can only be described as vicious, violent and sustained," the Sudbury judge said.
When he delivered his decision, which followed a nine-day trial that took place in January, February, May and June of this year, Buttazzoni indicated there was no apparent explanation for the assault.
Duplin didn't take the witness stand and there was no direct evidence of his intent.
In this case, the strongest evidence of intention to kill is the nature of the assault, the judge said.
He pointed to Duplin's attack - a number of forceful blows to Paquette's head, a vulnerable part of his anatomy, with an "imposing weapon," a machete with a 16-inch long and three-inch wide blade.
The assault continued even after the victim raised his arms to defend himself and didn't stop until Paquette yelled at his uncle.
Buttazzoni said he also considered the evidence of an expert witness, called by the defence, in assessing whether the accused had that intent.
Dr. Matias Mariani, a clinical and neuropsychology expert, concluded that Duplin suffers from a mild neurocognitive disorder and several psychological conditions.
The judge said Mariani's evidence confirmed Duplin's cognitive limitations and intoxication would have affected his judgment and decision-making.
"That, however, does not equate to an inability to foresee the consequences of one's actions."
Duplin's actions could very well have been impulsive and not well thought out, Buttazzoni said, indicating he had "clearly made a very bad decision and exhibited very poor judgment."
The accused's level of intoxication, while ambiguous, may have contributed to the poor decision-making, he said.
"Nonetheless, one can be impulsive, and still intend the consequences of his conduct; one can exercise poor judgment and still intend the consequences of his conduct."
Breath samples taken by the Ontario Provincial Police following Duplin's arrest revealed readings of .110 and .091 milligrams of alcohol in 100 millilitres of blood.
"Without an expert to interpret these readings I am not prepared speculate as to (their) evidentiary significance," Buttazzoni said.
He noted Paquette had testified that neither he nor his uncle were intoxicated.
The 55-year-old man had known the accused for a long time, and they had drank together numerous times. "He would have been in a good position to assess his uncle's state of intoxication."
On Friday, Buttazzoni heard how the assault has affected Paquette, who "suffers pain every minute of every day," from the seven blows to his head and 15 to his hands and arms.
"Every time I look in the mirror or at my hands I'm back to that night," he said in a victim impact statement, which his sister Danielle read to the court.
Paquette, who underwent reconstructive skull surgery following the attack, and had part of his left index finger severed in the assault, said he has limited mobility from damage inflicted to tendons in his hands and arms.
"I need help with everything," he said, indicating he doesn't like to ask for help, but must - something that is hard to accept since "I have always been independent."
He doesn't sleep well, has constant nightmares and irrational fears, is unable to trust anyone, can't think straight anymore and forgets things.
Paquette said he struggles to make sense of what occurred, and questions why his best friend turned into his worst enemy.
"Why he did this will never be answered. I'll never know why," he told the judge.
"Andre is a selfish coward who preyed on me in my most vulnerable state, while sleeping," Paquette said, calling this a scary thought that leaves him fearful.
Buttazzoni also found Duplin guilty of assault with a weapon and aggravated assault in connection with the incident.
At the request of prosecutor David Didiodato he stayed those two counts.
The assistant Crown attorney and defence lawyer Jennifer Tremblay-Hall will make their sentencing submissions on Thursday.
Outside the courtroom, after the judge delivered his decision, Tremblay-Hall indicated the conviction will be appealed.
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