As was said, it is your house and he is a (now) unwelcome guest. Tell him to leave, if he refuses or gets violent call the police to have him removed. Actually first I would contact a domestic violence center or line and ask them how they would advise you to proceed, since you don't know how he will be once he's out of pot and out of a house too, and they will have experience with how you might prepare yourself. THEN, tell him to leave and involve the police if necessary.