What exactly is the reason that I can't quit smoking? 😢

There is someone in my house who has been smoking almost continuously for about 30 years since high school. When they were young, their body could probably handle it, but now that they are older, I wish they would quit for the sake of the family, considering their age. It seems difficult to change a lifelong habit... It's not just about health, but I feel like I might go crazy from the cigarette smell if they come close. These days, they say vaping is better, so they make excuses... but to non-smokers, it's just as unpleasant. Moreover, the side effects of vaping haven't been fully verified yet, and it's said to be even more dangerous... I really feel like I might lose it.

My nagging and scolding don't seem to work at all, so I've tried using the kids' cuteness and doe-like eyes since they were young, but it still doesn't work. I'm really worried that this might cause serious health issues someday. Since they don't seem to feel much of a sense of crisis, I can't even send them to a smoking cessation clinic... Quitting smoking is so difficult. Is it really this hard to quit smoking? ㅜㅜ