Sometimes I wonder if Michael is not only sadistic but also insane. Here he is wanting Terri to die, yet he had her parents kept for a while away from her bedside because he claimed, they would harm her. He is the one who would not even allow flowers for her or have last rites.
In Michael's view her parents are harming her by trying to keep her alive and treating her like a human being. She ceased being human to him a long time ago.