As noted just above, I agree that Michael's behavior is largely irrelevant, except inasmuch as it affects how one interprets and weighs his testimonial evidence regarding Terri's wishes.
But I don't see PVS as the critical issue under Florida case law. If the patient is mentally incapacitated (could be dementia, altzheimers, stroke, brain injury, insanity, somehow incompetent or unable to give orders for medical treatment), and is being fed other than by mouth, then that patient is a candidate for natural death by dehydration.
IMO, the critical issue is the determination of the patient's wishes.
I'd have to go back and look, but I've viewed it as a fallback argument for Michael if the "Terri's wishes" argument had failed.