Given my history raising a similar child, if this were my child, I would ask that the learning support people help you get him OT for his handwriting difficulties, and perhaps the use of a scribe for classwork until the handwriting improves to the point where he is able to get what is in his head out on the paper. We started my son in OT at age 5, and provided him with a scribe and training in keyboarding as well as handwriting instruction. This was incredibly helpful to him in reducing his frustration with written work. The motor difficulties/handwriting issues are characteristic of Asperger's, as is the odd prosody. The psychologist who diagnosed my son with Asperger's noted that although he scored well within the ranges for ADD inattentive and ADD hyperactive on the Connor's, most of the behaviors that qualified him on that scale were Asperger's traits, and he seemed to have few actual difficulties sustaining attention during the testing and assessment period.
You might want to point out to the people who tested him for CAPD that there is a huge discrepancy between his spatial abilities and his other intellectual abilities. If they cannot diagnose CAPD despite the evidence of depressed spatial functioning, that doesn't mean that looking into accommodations for CAPD would be useless. Because of his difficulty processing language in noisy environments, he may experience life as if he has CAPD, and the sorts of coping strategies and instructional supports that are useful in CAPD might help him be more successful in situations where auditory processing is needed.
