I just found out my friend is gay, what do I do?

Yesterday I found out my friend was gay. He never told me before but just sort of came out yesterday, not to everyone, but just to a few people including me. Well obviously I was really shocked and left i disbelief, and I didn't show him my reaction, but I kind of don't know what to do. He said that he's totally fine with it and isn't ashamed of himself, and says that he...Don't want to imagine it. Anyway, I don't know what I should say to him, because as soon as he told me I tried to navigate away from the subject.
I'm still his friend, gay or not, I just don't know what to say to him and I can't exactly avoid the subject.