Cory Barry, 42, was sentenced to life in prison for the second-degree murder of 15-year-old Justin Wendland.
The Wendland family had asked for parole eligibility in 13 to 15 years, but the B.C. Supreme Court judge refused to impose more than the minimum 10 years before Barry can apply for parole.
After the verdict, Wendland's sister Kayla said the family, and especially her mother, Raj, are struggling to come to terms with the murder.
"It's really hard. She's a single mom. My brother used to do everything and he was such a good kid," said Kyla Wendland.
"She's never been the same person.... Sometimes, she's just so sad that there's just nothing you can do and I feel so helpless," she added.
Barry confessed to police he stabbed Wendland because he believed the teen was part of a gang that was out to get him.
A psychiatric report found Barry to have a mental illness and anger issues that are compounded by his drug abuse.