Complicating it further is that she is not terminal and does not require extreme measures to keep her alive (I think that this is probably the strongest relevant argument). The moral premise and argument for Right-to-die not being suicide is that the individual is terminal and that further treatment only extends suffering - that the treatments main effect is to force the extension of suffering. That is pretty clearly not the case here.
Regardless of how this works out, this case sits within the gray area, and attempts to legislate a response in this case will likely have a bevy of unintended consequences.
Her husband legally cannot be her guardian. If those laws were followed, a new guardian would be able to call for a de novo trial on the basis that he was not present for the old one (best to have a formerly-uninvolved Schindler sibling become guardian for this). At that trial, without Michael sandbagging Terri's condition, it would be obvious that she was not PVS and there'd be no reason whatsoever to deny her reasonable care.
This is a nice phrase. But all government is known for its "unintended consequences." One uses the ammunition at his disposal, or he forever will wonder about he outcome.