What you're feeling is so normal, it's hard coming to terms with something like this for your own self and to deal with it when it's a child is much much much harder.
Find your center and fill it with positive things. It can get worse and it can stop where it is and it can fill back in some from what I've heard.
I have a couple of friends, they are female cousins. They both went through periods where they were having massive stress and one had huge spots on her head go bald. She medicated and worked on reducing stress, sometimes divorce is good for that, and her hair grew back in an okay/presentable manner.
She uses products for fine hair to give it body and teases it to make it look thicker.
Her cousin had some similar stress and started having bald spots but it was a couple of years after her life had settled down. She is now bald and wears a complete wig.
The docs don't know how this happened and why one did one thing and the other went the other way.
I hope your little is okay through all of this because it could be worse, I know that's not much to hold on to but it could be something life threatening.