I encourage Adam to join to the forum and express his story.
He is the owner of the home so I would hope he would have had Paul sign some sort of renters agreement. If he did and a part of the agreement has been violated somehow he may be able to get him evicted.
I know in my state you don't need any agreement if you are asked to stay with someone and you are there more than 48 hours. It is some sort of "squatters law".
Might be time to tighten up the boot straps and start researching how to get him out of the house - IMO.