Thank you for sharing your experiences. I am sure it was painful to go through as a loving caregiver and observer. I am thankful that my husband is so oblivious to his own difficulties.
After my husband developed afib, he got weaker and weaker. As he lost the ability to walk safely, I tried to get him to use a walker, but he generally refused. After that, he started falling, and he was soon confined to bed. For him, as his rapid heartbeat wore him out, the end came quickly. He was only confined to the hospital bed for two weeks. We had Hospice last six weeks.
My husband also has a fib. He also was diagnosed with myasthenia gravis (for about ten years) and within just a week of him having the battery replaced in his pacemaker, he became unable to walk. I think it was a combination of all these factors that caused him to become unable to walk. He was given a standard wheelchair for several weeks and given therapy to help him stand, and finally, he became unable to walk at all.