"For better or for worse, in sickness and in health." Bully for the husband, I say - this is the worse, all right, and the sickness too. The one good point about this whole story, I think, is that he realizes that. She has a much better chance for some kind of recovery with his support - although (in total ignorance of any facts) one does wonder where he was with his support the last 7 years).
Also, the clinical variety of depression can easily be triggered by events, environmental factors or the fact that nobody would listen. The predisposition isn't usually enough.