I don't know what state your dad taught in, but that makes a difference. In some states, teachers are poorly paid. HOWEVER, I live in Illinois. My ex was a teacher -- just retired IN HIS 50s. He was making close to $100K at the end. And he taught the same classes (at the time I was married to him, anyway; can't say what happened later) and after the first few years, he never brought work home. Unfortunately for me, his pay was quite low in the early years but he did very well in his later teaching years.

It depends on where you teach.