In any legitimate proceding, if a guardian wants to do something which might not be in the ward's best interest, a guardian ad litem is supposed to be present to oppose the action and force the guardian to prove, over the GAL's objection, that the action is, in fact, in the ward's best interest.
When Terri had guardian ad litems that opposed what Michael was trying to do, he had them fired for opposing him despite the fact that it was their job to oppose him.
Net effect: in most proceedings, Terri had zero representation by anyone who didn't want her dead.