I've found it to work the other way. When you're old and sick, you're very tired and you know it's your time. Still you don't want your family to suffer and you want to be loved and have your friends and family be proud of you. It's they who have to give YOU permission to let go.

You HAVE to take care of this while you're still vital. A living will with clear instructions. And be nice to your kids and pay for all of the arrangements. That's one of the greatest gifts my mother ever gave to me.