My parents are hoarders. I can tell you from experience that this is a severe mental illness, often associated with other mental illnesses.
My father threatened me when I told him I had to move his things out of *my* house. Hoarders can be very paranoid, and occasionally violent. I left my family of origin and made sure they do not know where I live now.
Yes, get her out. These people are incurable, and they will destroy your house. Be careful how you get her out. Let the sheriff put her out, not you. They can get very upset and even violent if you "touch their things".