If he doesn't already know the answers to these questions, he's got no business selling this product. Everything that they're asking for—essentially the owner's manual, product requirements, and test methodology—would be readily at hand for any serious operation.
You can't just wire up an Arduino to the CAN bus of a 4,000-pound missile and sell it on the open market willy-nilly.
You can't just wire up an Arduino to the CAN bus of a 4,000-pound missile and sell it on the open market willy-nilly.