hi everyone this is my first post it's really nice meeting you all!
anyway if you just ask him to leave and tell him that it's really not cool with you that he's selling drugs he'll leave. if not then call the cops repeatedly. Im sure if you're polite at first then make it clear to him that you're a narc (snitch) he'll leave asap. Actually calling the cops would be pretty extreme, but if he wants to take it there...