Boy Chickadee, you've raised a hard question.
Apparently, this woman did not make her wishes known to enough people. So we will never know what her wishes truly are. It sounds like you suspect her husband of foul play.
Her parents' hearts must be broken and in turmoil.
My "personal" wishes are to be left to die in dignity and I have written orders everywhere, and everyone in my family knows I am not to be kept alive by artificial means or any other unnatural means. Including having to help me swallow. I shudder to think of choking to death, which might happen to this woman. My entire body is also to go directly to the university medical center for use as they see fit. No burial. Only a memorial celebrating the fact that I am truly home, with God, and not suffering any more.
I faced a similar type of decision with my mother who was dying of cancer. In the end, no life support of any kind was used. She was morphined into a coma and then died relatively peaceful. It was agonizing watching her choke and panic.
I don't know if there will ever be a good answer to these questions. My personal belief is God will handle it if we let Him handle it. When we step in and take the decision out of His hands, are we going against His will? How do we know if our decision is, in fact, His will?
If my children are all saved and in no danger of going to hell, then I would let them go peacefully to the home God has made for them by His side.
If they aren't saved, and two aren't, then I would probably hold onto them as long as possible, with the goal being to try to get them saved.
If this woman can hear and understand, and she were my daughter, and she was not saved, I would be praying and fasting by her bedside for her salvation. I trust God would make it apparent when it is time to let go.
As to that, my prayers are for the parents, their daughter, and the husband. God's Word states that men shall leave their parents and other things and cleave to his wife so that they are one. If he is a Godly man, then the parents should respect his place as the head of his wife and trust his decisions.
Wouldn't it be nice to know what all the facts are?
I'm grateful to not be in the situation.