Brother got fucked up

Ok look. This isn't just a question of normality or wtv but I really need some fucking help! My brother (who will be 16 in a couple months) is pretty popular and hangs out with the popular kids. Well I know he went out to a party and just came home and his friends carried to the couch and dipped ( at 2 AM). This guy reeks of alcohol (I know because I've had beer a couple times) and is like FUCKED UP. I know he's had to have hard liquor too. He threw up a couple times and it's so bad that me and my dad took off his clothes to kinda clean him. We left him in his boxers with such ease (as in if he was a female anyone could have had their way with him). But then my dad (on the note of how easy it would have been to take advantage of him that I said) took of his boxers to check for injuries or wtv, nothing weird he's a physician. But now my brother keeps... Idk how to describe it but it looks like he's doing situps. That sort of motion like a seisure or someshit. I know this is his first time drinking so I hope he's not dead or anything perminent happened. My god this is so sad. Somebody please tell me if this is normal? (Really just tell me wtf to do)