Help my friend is depressed what do I do :(?

My friend is gay (open just to a couple of people and not everyone yet) and has this crush on this one straight guy, and he is the person my friend fell hardest for. Everyday during lunch he just watches the guy he likes and is just in the most depressing mood and I can't stand seeing him like that I ask him if he's ok becuz I'm worried about him he, he says he's fine but u can tell that he's just saying that. When he txts me he tells me that he likes him a lot and he fells so sad and he hates himself for being gay and like this one guy. He also cries himself to sleep everynight. It's getting worse everyday to the point where he doesn't eat lunch and just sits and looks at him with his bookbag on his lap and were I can't even talk to him any more. Today at school he looked like he was about to cry but didn't and he's parents no nothing of this including that he is gay and I no i was to say something to his parents when they don't that he's gay it will just make things worse for him since their parents are very anti-gay. Wat can I do for him, I already told him I'm here for him and everything but he says he justs wants to be alone. I'm worried for him what can I do!!!! btw I'm the only person that he told that he liked willingly and some girl found out he was gay and wanted to no who he liked and made many long fb messages about how he's not saying and one of her friends ( he hates this girl) read the messages and also wanted to no and threaten to tell who he liked to her and of he didn't she will post on fb that he was gay and he ended up telling and she has told others nothing about it for all I no and btw the fb was during last weekend. Please serious answers