in reply to @sueinmn Thank you Sue, for this advice.
I will at some point make another attempt to contact her "person." I do know that she has blocked my number, but I do know she has received my text messages. These two, "Joyce" and Jan, have a long history of being friends for over 50 years etc,. and Jan has more than enough money to help Joyce. I have never asked her for anything, other than to contact me so that I could discuss with her the fact that I wanted to call Joyce's doctor and wanted her permission to do so. For some time I thought about going through one of the County's programs that pays for In Home Health Services so that I could at least get paid for what I am doing, as Joyce qualifies for the program with her age alone. But, it is a big hassle to apply for the program, set up an account and things of that nature.

Honestly, I end up feeling guilty if I do not go over each evening because Joyce has been very generous to me in the past, and even now if I needed something, she would do what she could within her power to help me. Her car was stolen about 2 months ago. Another long time friend of hers took her to the car dealership where Joyce ended up purchasing/financing a $40000 car. When the first payment arrived, she had not realized what she had done, and obviously could not afford the payments. Her friend paid the car off and is now begging me to renew my driver's license so that I can drive Joyce to and from wherever she wants to go, like to get her hair done, banking and things of that nature. I told her friend last night that I am unwilling to do this at this point in my life. It was hard enough being a passenger while Joyce was driving, I can only imagine what it would be like "driving Ms. Daisy." The car is beautiful, has all the bells and whistles, but is way too much of a car for someone like Joyce. She is not driving anymore, which is a good thing because she had been engaging in "road rage" and things of that nature, which were of concern to me.

Now that she has begun to act abusive towards me, it is all I can do to just ignore her and tell myself that it is her disease, not Joyce, if that makes sense. I do her laundry, cooking, cleaning, grocery shopping for which she gives me money (for the groceries and $20 to do her laundry when I remind her it needs to be done). I am putting this out there so that people know I am not taking advantage of her, as many do to people when caring for people who have dementia.

I have tried over and over again to describe to her the health crisis I am currently facing, but she either doesn't understand, or doesn't want to because she hates doctors and rarely goes to see one.

You are correct in that if I am injured or overwhelmed, my resources are somewhat limited. My older sister is dealing with her 73 year old husband who has advanced dementia, and she is having a very difficult time herself, so I try not to overload her with my own issues. In fact, I will be going to their home this weekend, and she warned me to be prepared for the huge change he has undergone since I saw him over a year ago. I don't know how she does it, and she often tells me to just stop going to help Joyce, but for the present time, I am not going to do that. I have arranged for a friend of Joyce's to take over while I am at my sister's house this coming weekend. In fact, I am thinking about telling Joyce that I am not returning on Saturday, but rather later, as I just need a break. I know this must sound selfish, but currently I am a wreck because of the breast lump I found a week ago and will have diagnostic testing done this week. More than likely they will do a biopsy because of my prior history with breast issues.

In any event, thank you very much for your kind words of wisdom. I think I will write a letter to Jan and spell it all out as you have suggested.
Again, thank you very much for your understanding and support.