Paying child support beyond the age of 18


I’m curious to know what people think about this.

My husbands step dad has two children, both over 18. In the custody battle, the agreement was made that both children would receive x amount every month until they were 26 years old. One is a teacher and makes good money in New York. The other is in school. (They’re 24 and 19)

I’ve personally never heard of anyone having to do this, but that’s what he agreed on.

So my question, do you think that children over 18 should still be able to receive child support? Once they’re 18, should it become optional for the parent to pay? If finances change and the parent can no longer provide the money while living comfortably, should it stop?