Give yourself an early Christmas present and tell them to get the fuck out.
I had a friend do something similar - he was in between houses, we offered him our couch and he ended up staying for almost a year. The icing on the cake was when he borrowed my car and then lost it after a night of getting shitfaced. At that point we told him he had to be out by the end of the month.
Yeah. It was in the middle of a parking lot. The cops actually pulled him out of it and drove his ass home - he had passed out in the driver's seat. The poor car smelled like a hobo had died in it, and he had an unopened twelve pack of beer in the passenger seat.
I had already had suspicions of him being an alcoholic, and that pretty much sealed the deal.
I had a friend do something similar - he was in between houses, we offered him our couch and he ended up staying for almost a year. The icing on the cake was when he borrowed my car and then lost it after a night of getting shitfaced. At that point we told him he had to be out by the end of the month.
I had already had suspicions of him being an alcoholic, and that pretty much sealed the deal.