Age and type of crime indicate to me that he was another schizophrenic. It usually hits around that age, and really spins up fast. He likely got some wild idea in his head that ran away with him. Unfortunately, it happens, even in affluent families. Don't try to figure it out more than that. It will never make sense. If he was schizophrenic, it only made sense to him. I wish there was something we could do for folks that begin to slide down that hill. As a pastor, I have had many such folks pass through my sphere of influence.
May the Holy One be with the families in their time of sorrow.
Rich P