Until he realizes that the life he is living is unsustainable (it will most likely kill him if it continues) for himself and anyone around him, that being sober is the only and much better alternative, that nobody can do it for him and that doing it alone is massively unlikely to be successful, there is nothing
you can do and staying in the mix will continue to take a real toll on you and the people around you.
He needs AA (arguably another addiction and/or cult but better than the one he has) and you are now a candidate for al-anon. Lastly and sadly, the odds are stacked firmly against his sobriety.
