Ok that adds another level. He likely has FASD and/or neuro damage due to the drugs on top of this all.
I still would consider out of home parenting. A start can be something like a 45 day inpatient evaluation. Or straight to a residential treatment center.
This kind of thing doesn't get better with the best of parents. And you will still be the parents. Just getting him a higher level of care.
And, your little ones are just too vulnerable. One terrible incident will be one too many.
You are really smart and strong. I love that you installed cameras. Keep them running.
Whatever you decide, your kids are all lucky to have you.
