What a nightmare. I am so sorry you are faced with all this. And no, in my opinion, you are not overreacting one bit. It seems a bit of an odd story that this has been going on for 5 years and she hasn't been seriously hospitalized. I wonder what else they aren't telling you.

Who is responsible for paying the rent or mortgage on the place you are renting? That worries me. What kind of lease did you sign? Should you be looking at another place?

Sending you support and positive vibes.