My Father In Law Had A Major Brain Aneurysm 3

My father in law had a major brain aneurysm 3 years ago, he has been in a care facility and has total care, he cannot eat, walk or toilet himself. He currently is suffering a bad cold that is causing breathing difficulty. The medical staff have stopped feeding and hydrating him as he cannot swallow now. My question is, how long will someone in his state survive without food and water??