This article from the BBC is remarkable. Check out the videos as well if you have time. There is so much we do not know about patients in this “persistent vegetative state” and instead of using starvation and dehydration, the most merciful thing we can do is care for them as we would anyone else.
Dr. Adrian Owen, co-author of the research, was also involved with a patient in a similar state named Kate. Her story can be found on YouTube: