No-one usually changes because you've asked them to, only because they wanted to so either we hang around hoping the change will come sooner rather than later or remove ourselves from their lives and wish them the best of luck.
I stuck around far too long and nothing changed, lol. Back then, my boundaries (if i had any) were so blurred because i kept on listening to him and trusting his word so i ended up becoming the crazy one. I found the best way for him to change (if that's what he wanted) was to get the hell away. If someone else wants to deal with it, great but there comes a time when enough is enough.