While I won't say I know how you feel, I will say I've been that family member who caught themselves sighing. It is a terrible thing on both sides. I don't believe my father has brought this up, nor has his doctors. We live in Oregon so this is an option for him if he wants it. He's already signed an advanced directive and let me and my mother know his wishes as to care. (Car accident for example.)
Does the possibility for abuse exist? Yes. It is limited in every way imaginable, but it still might happen. Similarly an advanced directive can be open to such abuse. That said, I much prefer these to be rights people can exercise at their discretion.