You need to do get to the point of having her removed.
At some point, you may be getting sued, because she is going to claim she wants to be paid for her labor for the time frame, she made all these improvements to your home. She might not win what she is asking you for. But she will most likely win something.
Plus depending on what type improvements this T made. She might have added illegal walls, wiring, plumbing, Who knows what else. If the work is not done to local codes with permits. It may be subject to be removed.
That is why any Landlord should refuse a T offer to do any type of repair. As a LL you are setting yourself up for injury claims and claims like this person is experiencing.