Health insurance copay deductible question for divorced family

Hello insurance people!

My co parent and I split things 80/20, me paying the 80, per court order. I have 95% custody.

They are on my coparents insurance, which at the time of agreement was slightly better than mine.

Coparent has changed to a high deductible plan. Now the copays for the kids are much higher, and going to coparents out of pocket max, etc.

This seems worrisome. Coparent isn't the actually spending the money toward their deductible, etc.

What are the legal considerations for this? Thank you in advance.