Another reason that might support testing would be if the universities he might apply to require this type of documentation in order to maintain his existing 504 accommodations in college. Some will want testing within 5 (or 3) years, some will want adult testing--both situations that require re-testing. However, the same caveats apply: universities are allowed to make their own determinations of which accommodations apply based on the evaluation data, so no guarantees no matter what the scores are.
