New twist for failing 18 year old senior

We have just found out that my husband’s son is taking a “medical leave” from school (although he is not ill) because, in his own
words, he “needs a break”. Of course, he has just been absent for 3 full weeks of school and hasn’t been doing anything other than failing the courses he is taking.

So, my question now is, if he does NOT go back to school, are we obligated to pay support? This “young man” does NOT have a job or driver’s permit or license. Would a judge say that if he “chose” to pull himself from school as an adult, that he would need to take care of himself? It would be worth going to court over if we had some insight.

Thank you,