So sorry - it is infuriating, but we cannot control others behaviors.
XAH lied about his course load - came out in a session with family therapist about co-parenting.
He was earlier claiming he did not get extra hours, in co-parenting sessions he mentioned that he has as many extra hours as possible hence I have to be flexible with allowing him to drop off DS earlier if “he is tired”. There was absolutely no reason to lie - child support does not change. He lied just because it fit into his narrative of being broke.