Hi, My Grandfather Is 75 Years Old And Has Diabetes.

Hi, my grandfather is 75 years old and has diabetes. His toe got infected and black, which i beleive is called "gangrene". He had to get his toe removed in surgery, to avoid the infection spreading further to his leg and so on... He had a heart attack though, so they didn't do the surgery yet. He's had another mild heart attack since and now he's under a heart's doctor supervision who says his heart is working at only 20% ! How could that be? He was fine a month ago, heart wise. Now they say you has kidney disfunction as well. Is there still hope?