Ugh, my mom's like this, too. She's made attempts, but she falls back on them from the withdrawal. I get quitting smoking is difficult, but when they don't feel the disappointment or shame of going back to their bad habit, it's like you do those for them, and that's when you know it's pointless to nag them about it if they're not even going to listen to you, increasing the distance between you in the process.