A relative of mine was in a similar situation. The more people pushed him to quit drinking, the more he dug in his heels. What finally helped was working with a counselor who used motivational interviewing. Instead of arguing or pressuring him, they explored his own reasons for wanting a different life. If you're trying to understand the approach, I found motivational interviewing vs cognitive behavioral therapy  to be a solid overview. It explains what motivational interviewing is, how it works, and why it's often effective for behavior change. For some people, discovering their own motivation works better than being told what to do.