Is my best friend gay

Maybe ... If he's your best friend, you should be able to ask him. A lot of gay men (especially kids) are "in the closet" -- keeping their homosexual feelings hidden -- because they fear they will get harassed in school, thrown out of their homes by their parents, or just because they feel ashamed of those feelings. The best thing you can do for your friend is to show him you don't like to see gay people harassed. If he sees you standing up against bullying and harassment, it may give him the courage to come out to you.