His mental health declined until he murdered someone. It’s not that he is “batshit”- he had a very serious issue that he could not manage on his own. When you isolate from others, can’t work, and only focus on your own pain and violently hurting others until you do it- you are not a healthy person who can mange your own affairs. To me, it’s no different from saying someone “deliberately” slammed their head into the wall, so they don’t “need” a room with cushioned walls.