How can help a gay friend who due to his homophobic parents and religious college he is being forced to go to? He feels trapped after realizing his sexuality. What can I do to best support him?

Listening to him and providing him a space space to be himself and express his identity openly is already an amazing help. You can also suggest him to get in contact with the LGBT community, many of them went through similar experiences and they can help him go through it and feel less alone. He could also start visiting LGBT associations, groups or events where he can feel free. He can do it secretely if it's unsafe for him to come out, and you could volunteer to accompany him if he feels uncomfortable at first. But most of all, just let him talk about it and express himself, it will make a big difference for him!

Well, I think being there for him is the best thing you can do for him. Maybe you can encourage him to talk to therapists and help him feel more confident and accepted. Coming out isn't easy especially to homophobic family, but he can try getting his parents to other parents who have accepted their gay children (not making it obvious) Just talking to them may help the parents get insights about this topic and help them slowly come out of the phobia and maybe by the time he comes out, they maybe in a better place of accepting than they're in now.