In between there is room for a wide range of personal choice - and without a living will, I don't think a guardian is qualified to use a casual statement as proof of an expressed "wish" to be used to terminate life when other family members disagee.
If Terri had truly wanted to die, she would have made a living will. Michael's claim (when it is to his benefit) to suddenly recall it eight years later totally lacks credibility. Also, it is the type of topic not usually of concern to those in their twenties.
I hate to think that we can be killed merely on the word of someone who has been proven to be a liar, adultere, and a vicious person filled with hate and has a conflict of interest.