He can always make extra cash by picking up a second job part-time. Where there's a will there's a way.
In AR, they would reevaluate the CS, and increase it based on the 2nd job, too. It's ~25% net income for CS for one child. It is increased for each additional child, but I'm not sure how much. My current had to pay it to his ex, and my ex was supposed to pay me. Guess which one did not pay.