My brother was married to a narcissistic self-indulgent pot-head for 20 years.
It used to drive me crazy because I too felt he deserved better.
Guess what? He's a grown man. He didn't need my input.
He finally divorced her earlier this year, and I had nothing to do with it.
I find it's best to work on my own recovery and life, and let the other adults in my life live without my interference.