Whats wrong with him (Please answer)?

Sounds to me like something happened to make him avoid you, and you obviously don't know what it is. I think you have done the right thing confronting him about it, and as long as he knows you don't know why hes avoiding you, but that you're willing to talk about it, thats about all you can do right now. Since he is one of your best friends, I'm sure he values his friendship with you also, and eventually will come around and at least talk to you about it. In the meantime, all you can do is wait for him to talk to you about it. So far though, I think you have done the right thing. I hope you get it all straightened out soon!