All my best to you J.
And I know how you feel. My own grandmother is in much the same state. She has been in and out of the hospital over the last year and she is 86 years old. The doctors say she could go at any time. I haven't had to deal with losing a grandparent since I was 14 and lost both of my grandfathers in the space of about seven months, one of which was more of a father to me than my real father ever was. And I lost my uncle last October after he also refused life support while my cousin, his son, was on vacation in Mexico. He didn't make it back in time to see his dad one more time, and it is eating away at him. So, do believe that I do know something of what you are going through. And I am pulling for you buddy.
May you and your family have peace of heart and mind in the days to come.