In this case, the government DID decide. Had the judge simply applied the law--no living will, nothing in writing: no case--we wouldn't be having this discussion. The presumption should always be to err on the side of life in the absence of other evidence. (BTW, are you aware that Terri was spoon-fed (another artificial method) for the first few years of her disability?)
I'm sorry, but that's not the law. The guardian is supposed to make the same decision the incompetent would make if they were able to make it.
Anyway, what is your solution?