I'm sorry to hear your mother passed. I, too, have a mother on kidney dialysis and she also has heart problems. (She had bypass surgery six years ago and she fell last year and broke some bones). I know the feeling of trying to protect your mom, and helping her enjoy life with all the limitations, and working around her dialysis schedule, trips to the doctor, etc. Just try to find some comfort in knowing you did your best for her while she was here and how much pleasure she obviously found in her family. Your mother's sense of humor was a tribute to her spirit, and that will live forever.
Joanne