You're getting confused by relying on Matthews. The argument was, I believe, that Terri usually followed Vatican opinion on pro-life stuff, and would have believed that she was putting herself in danger of damnation by wanting to disobey the Pope's recent speech on artificial nutrition and hydration. That is, the argument is that Terri would not have wanted to die, since such a wish goes against her religious beliefs.
This is my understanding of the meat and truth of this issue, as well, gbcdoj. Matthews RARELY gets thinks straight. And on the off chance that he *does* ever know truth that goes against his favored spew, he purposefully misleads, twists, and omits. Sometimes laughingly. Most times transparently.