@kj9- Welcome to Mayo Connect. My heart goes out to you. I also took care of my mom when she had Parkinson's and it was very difficult to make her eat too. I watched her pretty much diminish before my eyes. It's very difficult to care for a parent and she is very lucky to have 2 daughters to help take care of her. My youngest sister helped me immensely. Being the eldest I was my mom's main caretaker. It's important that you and your sister set up a system of who will be the main caretaker, make legal decisions if necessary, and speak to her doctor. It already sounds as if that is you.

As of October this year, I will be a 23-year survivor of lung cancer with 2 different types of lung cancer. I am presently at stage 4. I am not having any treatments right now. My son was very worried as you are. He lived across the country and found it very difficult to help me. I gave him the job of keeping everyone up to date on my journey by email.

When I had cancer I pretty much lost control of my whole being - everything centered around cancer and I had to rely on others for options and treatments - people who I had never known before were going to slice into me, remove an organ or part of one, drip chemicals into my veins, and hope to give me some time. I was 51 at the time. Just a pup. It was the scariest time in my life and I lost 5 lbs in a blink worrying about everything. I chewed valium on the way to every test, scan, and doctor's appointment. I was on the breaking point with each new step I had to take prior to my surgery. I'm wondering if your mom just came to a point when she couldn't take anymore then what she was dealing with and then along came another problem, her heart!

When I was in Chemo I lost my appetite too. The chemo that I was given really upset my stomach. No one in the world could get me to eat. But the idea that it was my choice was very important for the reasons that @artscaping gave you.
I'm wondering if the chemo can be making her ill. I'm also wondering why your mom was so upset about taking additional medication for a problem that is easily corrected with medication. Has she always been wary of taking medicine?