I had countless conversations like you describe with my RAW. After each one, I'd feel better as if somehow things would change or suddenly get better. I was only kidding myself b/c they never did. Maybe for a few days but she'd always relapse. Not until she hit her rock bottom and ask for help did things start to change.
The alcoholic in your life cannot stop drinking for anyone or any reason other than themselves. To attempt to somehow help them to stop drinking is futile and just creates feelings of hostility and failure against yourself. All anyone can do is take care of themselves. Create healthy boundaries of what is acceptable and what isn't. Only you can answer that for yourself. It took me several attempts at Al Anon to finally start to get the message. It's not an easy one to digest and it takes constant reminders. That's why so many of us are many years into our own recoveries well after our alcoholic achieves sobriety.