Can You Make Someone Gay?

I was a teenager at the time. Puberty hitting and always horny. My best friend was the same. We needed a sexual outlet. That led us to my 8 year old little brother. It started out with us play wrestling. We pinned him on the floor, pulled his pants down and played with his tiny cock and ass. We made him suck our cocks. We made him give us blowjobs almost daily. As things progressed we began fucking his little ass. We used him for our sexual outlet until he was around 13. It was the time he hit puberty and should have started getting into girls. He never did. He only showed interest in boys and came out as openly gay in high school. Was that our fault?