Should the ex pay for her classes this semester?

My ex and I decided that we pay 1/3 of my daughters school. The court said we are to pay 1/2 each. We decided she pay ass well so she will appericate it. Her last semester she broke up with a bf and was having a rough time with life ingeneral. She works full time and goes to school full time.She was depressed.I thought I might have to take her to see someone. Last semester she felt overwhelmed and drop two classes she was failing. One of the other classes of the 2 she had left she got a D. She is not happy with that and is taking it over. The ex says he is not paying for those classes again. I think he should consider she was in a bad place with life and having a very hard time and should pay. She is already paying for a 1/3 when the court says he should pay half. Please Help!