Well I don't see that being straight is any easier. Ask yourself this. Would you rather he go through the pain of lying to himself and getting into a relationship with a girl that doesn't make him happy, but that he is ultimately trapped in or would you rather he be true to himself and actually be happy?

My biggest concern would be how he goes about exploring his sexuality. There are just as many misleading influences out there for a young gay teen as there are for straight teens. He is still an impressionable youth and telling the fiction from the reality will be a challenge for him.

So one of the things you'll want to focus on is his sexual health. Experimentation is fine and is going to happen with or without your consent. But make sure that when and if he finds a partner that he knows how to protect both himself.

Maybe talking to his doctor will be a good place to start.