Have you spoken to anyone outside of AlAnon? This man is unstable and has access to firearms. I don’t want to fear-monger, but addicts are often impulsive and sometimes they hurt those around them when they decide to kill themselves. (A cursory glance at the news is full of men shooting their spouse)
AlAnon detachment does not extend to violence, threats of violence, etc. That is an emergency waiting to happen. Please consider talking to a counselor, a social worker, etc. You and your children’s safety is paramount. My best friend’s father saw his alcoholic father commit suicide via shotgun and has never recovered. This is an emergency situation and I hope you’ll seek professional intervention outside AlAnon.