<human>: Give me the gist of the text in a nutshell

My cousin lives about three hours away with the more conservative side of my family. Last October (on national coming out day, not like my aunt knew anything about that), he told my aunt that he might be bi. 

I've known my cousin all his life (obviously) and I think he might be gay but too afraid to bring it up. Our grandfather absolutely despises gay people and will badmouth them any chance he gets. My grandma is a little more modern, she tries really hard to be accepting of gay people, which is nice, even if she doesn't always get it right ("I just feel so bad for the gays, what an awful life to lead," etc.). 

That October, my aunt told my cousin to not tell anybody else that he might be bi and to forget about it. My aunt told my grandma, who told my mom, who told me, however, I was sworn to secrecy, because my aunt told my grandma not to tell anyone. This past weekend, my cousin asked my grandmother to take him to the gay pride parade in San Francisco, about an hour away from where I live. Our grandma would love something like that, but I'm not sure how they're getting it around our grandfather. 

The thing is, I would really love to tell my cousin that I'm here for him and everything else, but since he hasn't actually told me anything, I'm worried I'm doing the wrong thing. My boyfriend keeps telling me I don't even know if he's gay, but we used to dress up in our grandma's clothes together as kids -- heels, makeup, everything. I know that doesn't mean he's gay, but having known him growing up, I just kind of think he is. My boyfriend thinks I'm being stereotypical/judgemental, which I really don't want to be. If I ask him if he's gay and he's horribly offended, I'll feel terrible. 

I just want my cousin to know that I'm there for him. Should I wait for him to come to me? I'm definitely outspokenly liberal, so I know my cousin knows I would support him.
<bot>: Worried my cousin is gay without any family support, also worried my cousin isn't gay and I'm being as dense as my grandma when it comes to gayness