If he doesn’t sign enrolment/fees forms then he is not obligated to pay anything. Perhaps he can say send them to private and ill chip in here and there WHEN I CAN! Eg: school shoes, top up on uniforms, school photos etc.

My friend was forced to pay for his daughters private education. They had always agreed public. The kid went to public primary school but the mum decided she wanted private for highschool. She picked an expensive school and the kid wasn’t academic and didn’t do well. My friend said no but it was forced on him.

It’s all based on what their intentions have been. So sounds like it was always public. Unless she has proof they had agreed on private for high school, like an email stating that. Good luck

She can't make him, ie take him to court to make him pay. But the school can chase you for half the fees if mum says he is paying. You need to email mum and the school stating that you won't be responsible for paying fees, excursions, laptops, or uniforms. If you agree to pay you can be held responsible, so it's best to ensure you have a paper trail just in case. I say this as someone who is married to someone with an ex that would lie and have the school chase us for money.

Well if she is paying for it I don't see what his issue is?

If she agrees to pay then it shouldn't be a problem. If they dont agree and he cant afford it the next step is mediation or family court. You cant force your ex to pay for private schooling when all along it was agreed they would go to public school.