Help please? Uncle & Company Need them Gone Now...?

Alright, my Uncle is a Nuisance and me and my grandmother both want his company out of the house he and his friend have brought her husband over for the night ( thow i expect he will ask for more and more time here) that simpley are unbearable and both me and my grandmother agree he and them need to leave, he also has said that he is gonna try to ground me and take away my game systems and other items, now my question if he trys to take my things can i legaly have him arrested for stealing and if so do you think this would get rid of his friends?