Your State Judiciary published what is known as The Judges Bench Book, or something similar that guides your Judges statewide so that there is consistency in the State Courtrooms.
Included in the Judges Family Law Bench Book will be guidance on Contempt - you might want to read it as that is what the Judge will consider if your case makes it that far.
Reality is that the mother will find her attorney not so interested in Contempt, but in motions to compel or enforcement - and her attorney will tell about the grades/transcripts obligation.
I laugh a little at the mother's reply - did you ever hear about the University of California Santa Cruz and how they didn't actually have grades for a number of years? It was a failure of an experiment, and still the brunt of many jokes.
Volenti non fit injuria