Once he is upset, he appears to lose the ability to think rationally and stick to the truth. And he can transition from happy to meltdown very quickly based on the oddest triggers. We know some of his triggers, but we're often surprised by the things that set him off. Once he's melted down, his emotional age is that of a 4-5 year old, and he will often refuse to communicate using words. Instead he will "communicate" through abrupt body movement, grunts, stomping, growls, and mean faces.
I don't have much insight for you on treatment, but I think I'm raising your son's soul mate. Your description of his behavior and attitudes is eerily like my DD8 (3rd grade in a full-time gifted public school). She has been diagnosed with dysgraphia and sensory processing disorder.
I also think that a neuropsych evaluation is warranted, if you can possibly afford it.
