Hint: the law is wrong. Food and water are not medicine. I agree with the pope on this. In an extraordinary circumstance, they may be withheld, if they are doing more harm than good. The nutritional maintenance of an otherwise healthy disabled woman in MCS or PVS is not such a circumstance.
The law matters in a nation of laws.
Do you remember what Paul Scofield, in the character of Thomas More in "A Man for all Seasons," said to his son-in-law, who said he would cut down laws to defeat the devil?
“This country's planted thick with laws from coast to coast-man's laws, not God's-and if you cut them down-and you're just the man to do it-d'you really think you could stand upright in the winds that would blow then? Yes, I'd give the Devil benefit of law, for my own safety's sake.”
We don't cast aside laws when we don't like them. We change them.