To whom?
That was the problem - she never did.
Such desires, if they existed, would have to be expressed in a properly witnessed and notarized document (Living Will or Medical Power of Attorney).
Teri Schiavo never signed such a document.
Why do you suppose the law requires such a meticulously drafted document in the first place?
There is no such law. But such a document is a good idea. You can die testate, that merely establishes certain guiding principles and laws. It doesn't mean anything else.
In this case, the closest relative (the husband) gets to decide. If Terri told him her wishes, the court is LEGALLY and MORALLY obliged to follow up on those instructions, Greer-bashing anarchists notwithstanding.
I would prefer my wife to handle my affairs if I became brain dead (although I have Living Will on file, partially as a result of this case).
And yes, Terri was brain dead.
You are exactly right. Terri never put it in writing. And Michael "miraculously" recalled it only many years later after he received the money from a law suit for her rehabilitation.
There was clear and convincing evidence that Terri never expressed a desire to be euthanized. Aside from all the evidence provided by family and friends (which was substantial in and of itself), there was Michael Schitvo's own sworn testimony that he wanted to become a nurse so that he could fulfill his vow to Terri that he would take care of her for the rest of his life. When weighed against his later allegation that she casually commented that she "wouldn't want to live like that," it's pretty obvious he did not fulfill the legal requirement of clear and convincing evidence that she would want to be starved and dehydrated to death.