Almost anyone can teach, some teach well but very few actually enjoy teaching. You have to be very sure that this is what you want to do for the rest of your life before making such a career choice. It is very difficult to go back to industry after you have spent a few years in a teaching position.
He might consider moving to another company with better working hours before giving up for something he might not like to do.
For me at least, it is extremely important for one to be in a job one loves to do. It improves quality of life at and outside work.