A couple of notes:
Actually, his achievement scores really are commensurate with his nonverbal ability. Regression to the mean is one of the concepts that can be hard to grasp. The predicted achievement in all areas of academics, based on his nonverbal ability, falls largely in the mid 120s to upper 130s. It's actually his higher math problem solving score that approaches being above predicted levels (though not by much). I agree that the large difference between verbal and nonverbal is worth keeping an eye on, but it isn't that surprising that there is no apparent impact on academic achievement at the primary grade levels. Expectations are low for this age, especially for the high-level, abstract, inferential verbal reasoning that is likely to become more of a relative challenge for him down the road (possibly quite a long way down, and possibly not at all, since he has exceptional fluid reasoning).
We've already discussed ADHD, and I think someone brought up the fine-motor/dysgraphic category of learning differences. I think, whatever the etiology, the OT testing pretty clearly demonstrates fine-motor delays, which are sufficient to explain challenges in reading and writing, and the speech language eval documents pragmatics delays, which are likely to contribute to social and behavioral presentation, and may even impact reading and writing performance (because of the inferential aspects--though not so much at this grade level). Writing for obvious reasons, and reading because many teachers assess reading comprehension through written products. Unfortunately, your final eval report confirms that no norm-referenced assessment of written expression was done.
Granted, the OT data should be sufficient to stimulate an occupational therapy and a writing goal, and classroom accommodations to provide access to demonstration of skills in a variety of academic areas (including reading comprehension) without being gated by handwriting. If the school can be flexible about letting him use, for example, a variety of oral and visual presentations instead of purely written products, then he might have some other avenues for accessing ELA instruction. I would want to separate working on handwriting and mechanics from working on language expression, reading comprehension, social studies and science content areas. So don't grade for spelling (except as it impacts intelligibility) unless spelling is the instructional objective. Allow speech-to-text for writing longer than a sentence in length, and oral assessment in content areas and for demonstrating reading comprehension. Extended time. Items only sufficient to demonstrate mastery (graded on starred items only). (By the way, this would actually serve a dual purpose of helping with his slow writing speed, and, as a side benefit, reducing boredom from repetitive drills.)
