IMO that idea is a fantasy, wishful thinking. For one thing, Greer used a casual comment by Terri as proof she chose death over her circumstances. Secondly, he chose to believe that she was a "vegetable", (a term I deplore, BTW), despite testimony from those who disagreed.
Neither of these decisions could be applied to M. Schiavo, Greer or Felos, at that time anyway.
Yet each of them suffers a serious sickness themselves. They reek of evil.
It shows in their eyes and expressions. If you look at the various photos of each, you can see the empty eyes. 8mm