This is such sad news about your uncle. He is only 78...that is very young by today's standards. My mom has a friend that had bypass surgery in his late 80's. My husband had one at 55.
I just wanted to mention hospice care if your uncle doesn't already have it. My dad was also sent home to die (several years ago) and we had hospice care and it was the best thing we could have ever done. They have a nurse come over every day to check on them and when they pass away all you do is call them and they take care of all the details so you don't have to deal with it at such a stressful time. Mu mom couldn't have done it without their help.
Anyway, just thought I would mention it.
I know this is difficult for you and your uncle will be in my prayers.