What's wrong with my little brother?!?!?

Okay..My brother he is 11 years old and on Friday he came home sick from school. He was normal but then when we were asleep,it was about 12:00, i heard my brother yelling and saying crazy things, it was scary. then the next day it happened again at about 12:00. this time it was much worse. He was yelling loud and was running into my room and my dad tried to stop him. he kept on making those barfing sounds but he didn't barf. but it stop about 5 or 10 min later and then he barfed.