Hi and welcome to the MS community, your Autism question has landed
in the wrong community but we do have a some parents
in our community that have ASD kids so we still might be able to help you a little...
Firstly, I think you need to do is to get him assessed by at least an ear, nose and throat specialist, solutions differ greatly depending on the causation, surgery,botox, therapy, skill set training etc will only benefit him if the underlying cause is being taken into account.