They are trying to do "what's best" for her "interests". It isn't a "quality" life.
You'll notice that it is her caregivers who are giving up on her. She is not the one bringing the case, her guardians are doing this. Same as Michael Schivo. They don't always have your best interest at heart.
It's why there is spouse and child abuse too. Just because someone is "in charge" doesn't mean that they will make the right or proper decisions.
Can she be countersued for her existence?