If getting oral cancer is not a powerful stimulus to stop, then I do not know what is. At that point it is clear that you are not invulnerable even if all your family smokes and lives to a hundred. What happened once can happen again...... and with every drag you take you make this more and more likely. Scalpels, forceps and other such tools and the oral cavity/tongue do not mix well, the tools win every time.
All you can do is to provide information (such as a neck dissection) and point people to this site and sometimes it may just work. There are people that smoke in the parking lot before/after their IMRT treatments, which is not a smart way to spend health care resources.

M