What about her husband not filing proper paperwork as far as bieng her guardian? I'm not sure of the details but that's what I've read. And he has reversed his decisions several times so I don't see how he's following the law.
While related, it's still a side issue to the fact that Florida law allows the tube to be withdrawn. Fix that, and then you can focus on removing Michael as guardian. But at least there won't be the constant threat of an execution day for Terri.