While my ex-husband is considered to be the primary custodian of our 2 girls, I've had to step up a few times and make sure that they got the care that they needed.
For instance, my ex had been simply taking the girls to walk-in clinics when they were real sick, or if the school nurse requested shots to be done. I felt that they needed regular care by one pediatrician who could get to know them and be there for nearly every issue. My ex wasn't happy about it, as he feels that I'm always going to doctors for dumb reasons. (pet peeve between us, sorry) Anyway, I insisted, and he gave in pretty quickly.

It's been very helpful, as I've had to refer to the pediatrician a few times & she's been a big help!
I hope that your ex will look at your daughter with the perspective that she may require some professional help in dealing with what she considers a loss of close relationships. Best wishes to you both!