It must be heart-wrenching to have a kid like that. You know they are broken, and that there is no fix for them. Even worse, you are afraid for your life, their life, and the lives of your other kids.
I know that the number of mental institutions in the US has dropped precipitously over the last decades. They were awful places, but we could replace them with something better. The number of prisons has grown as those institutions have closed. It was a transfer of resources.