I don’t know if this helps..it may. I am a guy who has CAH (salt-wasting type), and when I was younger I put on weight on my butt and thighs like a girl would. I also was on Cortef and Florinef at the time.
After a while, that is after puberty when my hormone levels were not fluctuating so dramatically as they were prior to this, then everything started levelling out and I took on more male characteristics. And I also stopped getting sick and dehydrated as I did before.
Maybe it is working in the opposite direction for your daughter, and once her hormone levels start to normalize, then she will lose the stomach weight and take on more feminine characteristics.

Good luck with it, cause I know that age was the worst part of this disorder for me, but it corrected itself when I grew up, so alls well that ends well.

Take care