Welcome to sr. I'm sorry to hear of what brings you here.
You didn't cause it and you definitely can't control or cure it. If he doesn't want to stop drinking he won't.
Looking after your self is all you can do. He is an adult and no matter how much you love him you aren't responsible for him.maybe tell him you won't be enabling him anymore. You will be there for him to support if he decides to quit but he isn't ruining your life along with his own.
The bottom line is he won't quit until he's ready no matter what anyone says