One of my "straight" friends tried to have sex with me?

One of my close friends (I'll call him "John") has been acting very strange to me recently. John was a year older than me in my frat, and ever since I've known him has been quite the ladies' man (very good looking, very confident, always getting with lots of girls, etc).

But, since we've graduated college, most of the dudes in our friend group have gotten good jobs/serious gf's, and John hasn't really been able to get his shit together. He's been drinking a lot, he's gained a little of weight/stopped keeping up with his appearance as much, and hasn't been having much (any) luck with the ladies.

Recently, I've been questioning whether or not John is 100% straight. For example, he always makes tons of comments about my penis. All my friends do this to each other (we had communal showers in our frat so we're used to being naked in front of each other), but it's always super clear that they are joking, but when John does it, he somehow just takes it to another level.

Last week, though, shit got real. John came over to hang out/watch a movie, and we both ended up drinking a bunch and got pretty wasted. John kept on making comments about my dick again, and then he started wrestling me and trying to rip my boxers off of me, saying stuff like, "let me see your dick!". I stopped drinking after that, but John didn't and got blacked out. He then started blatantly trying to convince me to have sex with him, telling me stuff like, "We should fuck, but I should be the one to fuck you, because your dick is bigger than mine and I think it would hurt. Plus, I bet you'd like it if I fucked you in the ass!" He was laughing every time he said it, so he might have been joking, but I probably had to tell him "no" about 20-30 times, and he kept coming up and groping me and trying to cuddle with me, and also kissed me on the cheek several times. Also, he tried to get into bed with me at the end of the night and was legitimately trying to convince me to let him sleep with me. I ended up just letting him pass out and I went and slept on the couch.

I talked to him the next morning about what happened, and he admitted that he kinda remembered it and laughed about it, acting like it was no big deal. But i could tell he was embarrassed and super glad when i told him that I wasn't going to tell anyone.

What should my next move be? I wanna be a good friend to John, and I feel like if he really is gay/bisexual, I should share some of my own experiences with him and help him out. But I'm also worried that he'll get defensive if I tell him I think he's gay/bi, or that he will think that I wanna hook up with him or something. I don't think it would be a good idea to have sex with a dude who is 1) one of my close friends, and 2) seemingly a closet case. But, if I'm being completely honest... the whole situation did turn me on a lot, and I would be lying if I said I hadn't fantasized about what would have happened had I not turned him down. Idk... the whole situation is very confusing. I definitely don't have any romantic feelings for him, but the idea of hooking up does appeal to me. Any advice???