\\\\ Can anybody tell me is she putting herself through too much and will she get better ever\\\
I can't answer your question, but i can give a few simple facts.
High potassium in the blood can have devastating effects particularly on the heart.
For reasons not clearly known, cancer patients often have a high potassium, caused by the type of cancer and also the presence of distant spread (metastasis)
Chemotherapy can also produce a high potassium, due to it's side effects, so all these factors producing a high blood potassium can affect the heart.
Your question is a good one and one that can only be answered by the patient e.g has she just had enough.