Teenyuck,
Very tough call as to what to do here, eh? I detest liars, cheaters and thieves myself. However, JW's, in my experience have a strange ability to think that they are ABOVE the law. It is simply a product of their belief in being the chosen people. I have also never met a group of people, as a whole, that have very little regard for the environment, since they feel that God is going to clean the place up himself, anyway.
My point is simply that any action you may take will likely come back to haunt you, not because you deserve it, but because she thinks you do.
Jehovah's Witnesses' perception of reality is so far gone already that it is very difficult to REASON with them. Therefore, for what it is worth, my opinion is to have faith that she will get what she has coming to her. I would also suggest that she is ALREADY getting it. Can you imagine how f***ed up her mind is to try to pretend that what she was doing was OK and yet show so much hatred to the people that were going through their own hardship in the hospital?
I have gone through a ton of stuff with my mother myself and, while it is not always easy, I always try to remind myself that she is lacking a sense of self-worth with her despicable actions and my feelings are more of pity than anger.
Take care, Brad