Can you post a photo of the current braces.

If you're really looking to improve things for both your son and other's with similar requirements sponsor an undergraduate thesis at your local uni and encourage your Son's doctor to be involved as an adviser. Sponsoring an UG thesis will be relatively cheap (materials etc only) and if the student comes up with something with potential it can be taken to the "market" to get commercial sponsorship for a PHD thesis/commercial development.