Hello Sandy,
I think that's a very common attitude among many of the people our parents' ages. Unfortunately, they begin to see their health decline along with their friends, and it's difficult for them to see the glass half full (if I may). Let her vent, and be patient, I'm sure it will all work out eventually. You're a good daughter, and although she may not tell you that, she knows it in her .

All the best,
Chris