failure in your mother could be due to diabetic kidney disease or due to heart failure
due to poor blood supply to the kidney.
If the kidney failure is not recoverable CKD stage 5, she may require dialysis
In fact it is difficult to manage the patient with kidney failure and poor heart function.
It is difficult to say from your question without actually seeing the patient how frequent or how long she requires dialysis.
Your treating Physician or Nephrologist
would be better judge.