What is wrong with my boyfriend? He is really sick! Please help!?

He is 15 years old. He was sick all day yesterday, and all lastnight. He was ok today, then tonight he started puking again. He described it as, "feels like I'm dying." he is vomiting, has sharp pains in his stomach, it's difficult to breathe, headaches, his body aches, he doesn't have diarrhea or lightheaded. He does have stomach ulcers, but those haven't been an issue. He has had kidney stones before, and he gets kicked and hit on the groin on a daily basis. Please help me! Any info at all would help! Thanks so much! Oh, also I thought it could be food poisoning because he is on vacation in Florida, and has been eating alot of seafood. Please help!!!!!! :(