Re: General manners
So from the responses so far, I think its pretty clear that he's just a spoiled kid and that cultural divide isnt at work here. A spoiled brat is a spoiled brat in any flavor and taking advantage of a relative should not be allowed no matter what country you live in.
So...he'p me!!!! Now how to move on to getting him straightened out? With my boyz, I tell them do this or no dessert (or no playdate or I take legos away etc). How to deal with a teen who is (kind of) a guest but (kind of) not a guest? I cant take his computer away (its his and he needs it for homework anyway) and I cant ground him kwim? He is a child in an adult body and I just dont know how to interact with him.