Does this person have access to your home?
She used to have, I always had a second key to my apartment hidden in the stairways. She knew where it was, but I put it away before I left for the clinic. Call it instinct, but the weeks before I left, I already felt she couldn't be trusted anymore.

I would also avoid any possible contact with her
This is the same advice my doctor (who is also her doctor) gave me. But it won't be easy as we live in the same house (she lives one floor down).

However, they entire thing is so sad and scary! We used to be something like friends, I often went downstairs to chat with her, and she's also been a co-worker of mine. Now her disease turned everything into a nightmare.

Kirsten