If I am a vegetable and and water is all that is keeping me trapped in a such a miserable state of limbo, then by all means deny it.
It's preferable to suffering years on end.
But even at the maximum that does not give you the right to project that deprivation onto a person who did not ask to be treated so extremely.
What's "miserable" about being a "vegetable"?
If you are able to take in enough water and oral nutrition to survive for years, that would belie the "vegetable" label.
If you are a "vegetable" then you wouldn't be suffering. You wouldn't know what was going on.
If you had a painful, terminal disease, then maybe you would be suffering.