Is there a reason she is letting the battery die? I am paced most of the time and feel awful when not paced. My own heart rate goes down in the 40s and I feel wobbly, shaky, like I can't even walk. After being paced for 9 years, I am wondering why the pacemaker is not being replaced.
I understand the battery replacement is a rather minor surgery. Seems strange to me her doctor would say she is not a candidate "due to her other health problems". I would push for a reconsideration by the doctor as it reads like she may be stuck in bed without the help of the pacemaker. This is not a diagnosis or even a statement from experience, just and encouragement to be sure the doctor does his/her best to keep your mother's quality of life as high as possible.
Many times, pacemaker replacement can be done under local anesthesia. This is not a difficult procedure. Absolutely get another opinion!
I realize that you have a lot of history with your mother and her pacemaker, but modern pacemakers don't just "die". When the battery voltage drops to a certain level. The pacemaker will go into an "end of life mode" (battery, not person). It's sort of a last ditch conservation mode until the battery can be replaced. What happens then is the pacemaker will fire to a preset pulse rate. It will no longer take into account what the user's heart is doing. The is reported by some to be a very uncomfortable, miserable feeling. However, if your mother is pretty sedentary, she may not notice it as much as someone who is ambulatory.
I had a pacemaker for 11 years and the battery was finally draining quicker than usual. Unfortunately, the HMO I belong to in Northern California has a durable materials department that won’t allow the pacemaker to be changed until it has drained down and is in the “end of it’s life” mode. I was at a wedding destination 10 hours away when the pacemaker decided it was time. It was terrible; I could barely walk and had no energy whatsoever. Thank goodness, my husband was there to lean on constantly. We thought I felt that way because I had been having a lot of pain with plantar fasciitis because the tech never told me it was that imminent and I would feel like “crap” (her words afterwords). Lucky I had an appointment for a pacemaker check the day after we came back from vacation and had an emergency replacement within a few days. I feel like my health was put in jeopardy and don’t know if any damage was done to my heart. My life or their profit.