Oh, don't be afraid. I come in peace!
Caring for parents is difficult. I was lucky that I had a lovely mum, but it was still tiring, both physically and emotionally. My dad, who was a very complex man died suddenly out of the blue at 66 years of age. I'm approaching that age now ... eek!
I can only imagine how difficult it is to be constantly giving your sister support. It's not easy being the rock for someone else, especially when you're feeling overwhelmed yourself. It sounds like you may be experiencing something called listening fatigue, where you feel drained from constantly being there for others. Setting boundaries with people can be difficult, but it's good to give yourself a break. I don’t know how you feel in maybe trying to take breaks from answering your sister's calls, occasionally. One of my friend's once said that if you keep allowing people to do what they're doing, they will carry on doing it. Easy for me to say, though, but small changes can maybe make a difference.
Remember that it's okay to put yourself first and take care of your own needs. You deserve some time to relax.
You would do well in some of the writing communities. People might be in the same situation and they could offer words of support etc.
Look at us doing all this writing! I'm going off now to lie down. I'm knackered. 😝
RE: Meanwhile as our weather goes goes crazy in So Cal