If a PHD can’t afford to send his children to a catholic school, something does not add up.
A Ph.D. doesn’t equal a big pay check. Many Ph.D.s work for the degree because of the intellectual satisfaction, or because it’s a requirement in their chosen field.
Many areas that require a Ph.D. don’t pay that much, at least for quite a while into their careers. I.e., college professors.
And, Ph.D’s are usually 30 years old or more before they make a dime, frequently with serious college loan debt (which doesn’t sound like the situation in this case).