For what it's worth, when my grandma was in the hospital with congestive heart failure, the surgeon was very clear with her and with us that "do nothing, and die" was very much an option, and a choice that she and she alone could make.
I think this was the correct choice, but I have no idea.
On the one hand, she's feeling much better now, and I'm glad she's around, because I like spending time with her.
On the other hand, the recovery was pretty rough, though thankfully she doesn't really remember the truly bad parts. And she's 90 years old, and has repeatedly stated that she doesn't particularly want to go on living.
On the gripping hand, the doctor's description of letting yourself die of congestive heart failure sounded rather unpleasant, and hopefully instead of undergoing that, she'll pass away in her sleep.
On the hands that I'm running out of, maybe an even worse fate awaits.
Can't see the future. :/