There is a popular saying that goes like this "do as I do". What I believe this means is that action speaks louder than words.

The man still be smoking and keep punishing or enforcing his children not to smoke. It isn't done like that. To be honest, if I were to be the son of that man, I won't even listen to him.

It's now left to the man to build himself so that his entire family can give him the respect and follow him properly. Then after he has worked on himself, then he can make some corrections on others and they will surely respect him for that ( experience is the best teacher).