I knew he had been to rehab about a year before I met him for opiate addiction but aside from being a partier in the drinking sense believed him to be clean.
I'm sorry about the situation you find yourself in. Before I married an alcoholic, I also thought that going to rehab fixed things and all was going to be hunky dory. Sort of like you go to a hospital to fix a broken leg.
It sounds harsh but maybe his mother pressing charges and you cutting him out of your life is the biggest favor anyone will ever do him. That's what someone told me when I left AXH, that losing his family may be the consequence he needed to see of his addiction in order to get serious about getting sober.
Also -- with an actively using addict, I would not want him in the delivery room with me.