Providing a structure for them to live in is much better idea. But, still not great as far as I am concerned. Is there a reason these folks can't go stay with your Mom?
Hello and Welcome To BYC and Happy Holidays! X3 what enola said, you need to talk to a lawyer if your mom decides to go with this... there are so many possible ways this could end badly.
To be blunt, if you want to keep the property in your name (vs selling it or just walking away) and avoid further and likely exponentially more costly legal battles in the future, it's time to lawyer up and put an end to it all now, as it's only going to get worse in time...