Hmmm. . . It sounds to me like you are applying stereotypes to someone else's life. If you started eating fried chicken (to use a distasteful stereotype), would you be offended if I tried to convince you you were black? In other words, I don't think it is your place to "convince" someone they are gay and stereotypes are proof of nothing. I don't mean that to offend you. That's just how I feel. Even if he is gay, which feminine mannerisms is not proof of, do you really think it is up to you to "convince" him of it? That is something that is extremely personal. If he thought he was gay, but wanted to hide it, you're wrong to bring it up. If he has not yet explored that, but may be gay, he has to come to that conclusion on his own. You would, again, be wrong to bring it up. Lastly, if he isn't gay and you try to convince him is, you're going to piss him off. I had a gay friend who used to call straight girls lesbians all the time. She even went as far as to tell my mother that she thought I was a lesbian (not that mom would have cared). I thought it was extraordinarily rude. Firstly, I am sadly a plain old straight person. Secondly, it's nobody's business what I like to do with my private parts. 
