A boy in the middle school I work in has alopecia, and life has been hard for him because of it. He's becoming a lot more confident, I'm happy to say. He does wear a hat every day, and he wears it below his brow.
I don't think there are any cures, unfortunately, but I would love to be able to suggest to this boy's family that they consider permanent "makeup" to give him brows, at least. Also, they can make human hair pieces these days that look as natural as real hair.
I don't know at what age a child can have permanent makeup tattooed; because they are still growing it may not be possible until he is older, but it is a consideration. I saw RuPaul on tv the other day, and he had had his eyebrows drawn on for the day, it was masterful and looked just like real eyebrows. So you would have to research a lot to find an expert. It's not something you want to mess up, obviously.
But it's nice to know that the technology exists to make someone with alopecia look fairly normal.