Hi, I had gone through your question and understand your concerns
At the age of 72 ,of course it is not advisable to give another
stress in the form of surgery. In my opinion for any age , any condition
gangrene has to be removed from the body.
It is not that easy to get rid of gangrene by even with highest effective antibiotics with highest dose.
Because the body is even not have the capacity to burden the side effect of highly potent antibiotics.
Amputation is the only best and easy treatment just you have to take risk.
Once it is separated from the body the health condition improves a lot.
May be he will become more active after amputation.
And about answer for the days left, no one can predict it.
But sure that after removal of gangrene with health care and strict
glucose maintenance his life span will definitely increases.
Be confidant and give a trial.ALL THE BEST.
Hope for the good, lets have a surgery immediately.
Hope this answers your question. If you have additional questions or follow up questions then please do not hesitate in writing to us. I will be happy to answer your questions.
Thank you.