My cousin has 2 children he pays Child support for. His son recently turned 18 and has graduated from high school,does he have to keep paying for both children until his younger child turns 18 in the state of Maine?

What does the support order say, is the older one going to college? What does the support order say.

If support is to stop at 18, then the payment is adjusted, it shoud say in the order, if not he goes back to court to get it adjusted