That's a tough question. You just really want to make him happy, I know, because I am in the same situation. Mine has has congestive heart failure
for at least two years and she is very weak. She is on a low salt diet and a heart diet most of the time because she is in a nursing home, so when I take her out she gets whatever she wants. God Bless her. It is hard for those of us who love them. I really don't think it is going to make any difference in their life span and ask yourself "Does making him happy maybe add a bit of life to his life span?"....maybe it does. No one knows for sure. Just enjoy the time you have together and make him feel like he is loved and he is so important to you, as I'm sure he is. Good luck and God Bless you both.