The older boy, whose name was not released, was accused of slamming Mitchell Wilson's head into a sidewalk and stealing his iPhone while Wilson was taking a walk in his neighborhood in Pickering in November 2010. Wilson, who had muscular dystrophy and used a walker, sustained several broken teeth in the assault.
Wilson was found dead in September 2011 with a plastic bag tied around his head.
The boy's family said he took his own life after learning he would have to face his alleged attacker in court, the Canadian Broadcasting Corp. reported.
Craig Wilson, Mitchell's father, said his son suffered panic attacks and severe depression following his attack.
CTV News reported Craig Wilson said after the verdict the judge "followed the law right to the letter. I don't think Mitchell would have liked to see the law bent for his own benefit. We walked out respectfully with our heads held high."
Wilson he hoped his son's story encourages others to become more aware of bullying, and to treat others with kindness.
"I hope they get that being a bully and being mean and being unkind to other people for no particular reason other than that they're different than you or I just doesn't suit any purpose," Wilson said. "It doesn't suit what today's society needs to be for everybody to get along."