If he's an Aspie, there 's nothing wrong with him - he's special. He'll likely be a bit smarter than his peer group and retain an outside-the-box fresh and somewhat childlike perspective on things others tend to miss.
The hand flapping and gestures may cause some people to think of him as odd, but they're the superficial types who think everybody should be cast from the same mold. People smarter than that will actually find him interesting to know and be around.
On the downside, he may be very uncomfortable or awkward in social situations, prefer to keep to himself, so completely non-confrontational that bullies find him easy prey, and often even irritable when faced with sudden changes in (expected) plan, or drop-in visitors.
The actual testing process for determining diagnosis is kind of interesting - of course I was tested as an adult, so the methods may be different for kids. In any case, it's nothing to be afraid or ashamed of. it's an atypical brain function - just a different lens for seeing the world - it is not a disease. Neither he nor you should ever think that for a minute.
He's probably too young to appreciate it, but if you watch the sitcom The Big Bang Theory on Monday nights, there are two characters on it who are clearly Aspies - Sheldon has the behaviors of an Aspie child (although he's an adult physicist), and his roommate Leonard has the behaviors of a post-adolescent Aspie. Sheldon is clueless in social situations, but doesn't realize he's clueless and Leonard KNOWS he's socially inept, but can't seem to overcome it. Been there, done that. 