Welcome to SR ... we are glad you found us.
I know how hard it is to communicate that the behavior is a problem, trust me though he will not respond till he is ready to though... all you can do is prepare and get support for yourself. Maybe try going to Al-anon, there are people that understand and who knows if he sees that your serious about this, by attending meetings, maybe he will get that your serious... who knows.
In his response to you about turning to religion vs his turning to drugs/Alcohol.
1. One is ALTERING the perseption the other is focusing inside without alteration.
2. One is AGAINST the law while the other is not.
3. If he is on antidepressants and is also self medicating .... perhaps he should give up one or the other.... both change the chemistry in the body... and so he could cause more harm to himself.
Bottom line though is ... You cant control it, you did not cause it and you cant cure it. But you can educate yourself and start working your program so your better able to deal with it.