Do you think my friend is gay?

[Sam]

Me and this guy are both 14....he has a girlfriend and they have been dating for six months but he told me that they haven't kissed..he is a big supporter of gay rights and I called him a fag once joking over text and he replied "I don't want to be friends with someone that thinks that is an acceptable thing to call someone" one of his best friends is openly gay so is that the reason or is he too...? He says "I'm straight but I act really gay"...on twitter he tweets to famous guy celebs that he wants to go out with them sometimes but I really want to know...do you think he is gay? I want to be a person that he can come out to because I am completely okay with that and I want him to trust me if he is...please help!!!!