The Crown charged Brian Jordan Ense and Joseph Bernard Edward Ense with sexual assault contrary to section 271 of the Criminal Code.
The charges arose from an alleged incident on November 5, 2016, at a house party on Manitoulin Island.
The complainant, a 16-year-old girl, testified that she was sexually assaulted by both men while intoxicated.
Joseph Ense's charges were withdrawn after his death during the trial.
The court found Brian Jordan Ense guilty of sexual assault based on the complainant's testimony, DNA evidence linking him to the complainant, and corroborating evidence from other witnesses.
The court rejected arguments regarding continuity of DNA evidence and credibility challenges to the complainant's testimony, finding her evidence credible and reliable despite inconsistencies between her police statement, 911 call, and trial testimony.