There are psychologists all over who work with people with Non-verbal learning disorder as this is fairly common. I would suggest that you start your search with your insurance company's list of current providers, and then start calling psychologists on the list and asking them- the difficulty that you might run into is that most psychologists with a lot of experience in working with NLD folks are accustomed to working with them as children. Given that your son is 34, the kind of work they typically do with children obviously wouldn't apply. You might find that an occupational therapist could help your son as much as (or at least in a different way than) a psychologist can.
I'm also attaching a link with more information and resources about NLD in hopes that more of your questions might be answered- it might also connect you to a community of other people struggling with NLD for support in this. http://www.nldline.com/