That’s a good question, but a little complicated to answer without examining your son in person. A brief answer would be that Orthognathic surgery is indicated if the malocclusion is due to a skeletal discrepancy, i.e., misalignment of the jaws to each other or to the rest of the skull, and not due to the actual misalignment of the teeth. Usually, this cannot be corrected with braces alone.
There are some orthodontic skeletal growth therapies that can be achieved at an early age while the skull and jaws are still developing. However, after a certain age when skeletal growth has completed, if the skeletal discrepancy is severe, then most patients can never get a correction of the deformity without corrective jaw surgery. If patients do not want to have extensive surgery, then some can have minimal surgery to camouflage their problem, and some can do some camouflage orthodontic braces only. There are multiple different options for care.
Hope I answered some of your questions.
Tarek Korban, DMD, MD