Why will the husband accept no solution other than her death? Maybe because he promised her.
On the Today Show this morning, Michael Schaivo's brother named organizations and people who have offered his brother millions of dollars to do just what you suggest: hand her care off and walk away. He won't do it.
The case is under a microscope. What could he possibly hope to get away with?
To make him into the villain, when he has so much to gain from "just walking away", makes no sense.