Plan B: If she does pursue some type of remedy (legal or civil), you might request that mediation be done, either through the senior center or some other entity that serves the senior citizens. It seems that distrust and fear are primary drivers in the reactions that I've seen. No one wants to be treated unfairly - you or her. She may never believe anyone under her own age if someone tries to tell her that you've done a decent and competent job.
