People often say things out of frustration and anger. After time and space he had some time to think about it and is doing the right thing and IMO opinion that’s a good thing. If he becomes belligerent again then you can tell your children to not respond.
If you feel you had a no contact agreement for a few weeks and he violated your agreement then go ahead and send him a message about it. Again I’m not clear what is actually the problem with it and that is a hill you want to die on.
I get and completely understand you want no contact with him but he is their father and should continue to foster a relationship and be concerned about their grades as long as he is handling it in adult like fashion. The minute that stops then you can discuss with your kids about NC.
