ok ill try and go with just pertanit info

DH has 2 kids, the oldest turns 18 in a few months... He has dropped out of HS and doesn't seem ro have any plans ro go back or further his education (unfortunately)

We live in Canada

As per DH and BMs request child support is paid to a third party- family responsibilities office

My question is when and how does he go about stopping support payments for oldest child? Do we need a lawyer and file to have it changed by a judge? Will the agreement be re-evaluated based on his current income? (which he actually makes less now then when it was first arranged) does it happen automatically? Does he have to inform family responsibilities himself or will the court contact them?

Basically Any info would help especially if its from people who have went through this in Canada