How do you get a parent to abide by the court order regarding medical costs, etc?

Question

California law

Answer 1

The courts are the ones to enforce these orders. You need to document all the expenses, send a copy to the parent, along with either proof of payment, or the bill. If after a reasonable time these are not paid, you must file a complaint with the court, for failure to comply with the court order.

If it happens multiple times, the other parent will be subject to incarceration or fines.

Answer 2

He is in comtempt of court. Contact the Clerks office and report the issue.