I knew I liked boys from the age of nine or ten, but I did not have a name for it. Later I found out the name was "gay".
No, medication and creatine do not affect one's sexual orientation.
I think by saying, if there was a way for him to be straight, he would -- he was just emphasizing that this is *not* a "choice" on his part to like guys. He just does. But it's really hard, worse than being left-handed in a right-handed world, because at least nowdays, lefties are not hated or shamed by others. But often people go out of their way to be mean and hateful to gay folk.
Oh, and the crappy relationships with girls did not cause him to be gay. It is the other way around -- they were not his deepest passion, so of course the relationships were not satisfying.
You know your buddy and his good heart, and that he is a high quality person. The best thing you can give him is your love and support.
-- Make sure you HUG him next time you see him. He needs to know that you still love and trust him and treasure him as a good friend.
-- Don't be afraid of this issue! He thinks about it every single day, he has to. Every now and then, ask him, "Hey, have you seen any cute guys lately? Are there any guys in your dorm or at school you love to be with?" You see, he has NO ONE to talk to about this. Imagine never being able to talk about girls you liked...that would suck. So be a friend to him and ask him if he has noticed any cute guys, to let him know you support him and think he is fine as he is.
He is luckky to have a good friend like you who cares about him and does not reject him. Keep on being that good friend!