A new CDF document came out recently dealing with certain bioethical considerations of persons in a "vegetative state." It dealt with certain dubia proposed regarding the obligation to provide patients with food and hydration.
The document hands down two decisions: (1) Food and hydration constitute "an ordinary and proportionate means of preserving life" and must always be administered to a patient in a vegetative state so long as the person's body is capable of assimilating it. Only when it is not capable of assimilating them are caregivers released from the obligation of providing patients with food and hydration. (2) Even if professionals believe a patient may never recover from the vegetative state, food and hydration cannot be discontinued because the person retains their human dignity and must continue to be given the means of preserving their life, even if by artificial means.
Check out the document here.