I'm recoiling a bit from the "see if you can buy their place" answers. I know moving is a pain, but so is doing real estate transactions with people who are this level of inconsiderate--and so can doing real estate transactions with family be. How many letters have we seen that are of the format "I paid market price for a home some family member was living in and other family members are acting as though they can be in my business permanently"? I really really hate moving, I can't believe I'm on the side of moving here, but...might it be worth moving just to be cleanly disentangled from this?