When Is It Ethical to Withhold Food and Water?

Reading through a Herald Sun report on the final visit by Joe Korp to wife Maria Korp, I came across this:

""This is somebody who is not being sustained by the feeding," he said. "Her body is no longer able to process it (and) her injuries are so horrific that they are making it impossible for her to live even with this treatment." Mrs Korp's body was wasting away and her muscles were constricted, Mr Gardner said. "

This is only the second time that I've come across a report that Mrs. Korp no longer benefits from food and water. Earlier, the Archbishop of Melbourne had clarified:

"The Catholic position is that the person retains a right to nutrition and hydration until the body rejects it, especially in cases of terminal illness."

If such a condition is indeed satisfied such that Mrs. Korp's body is alreayd rejecting food and water, then perhaps the decision reached was justified. I still have this nagging question though: so how come Mr. Julian Garner himself, the public advocate who decided for withholding food and water starting Wednesday, has never mentioned that alleged fact about Mrs. Korp's deteriorating condition? I guess I'll never know. I don't need to know, but I do pray that everything that will happen concerning Mrs. Korp will be in accordance with the holy and perfect will of God. May the almighty Lord grant us all a quiet night and a perfect end. Amen.