My DS 7 1/2 had mostly auditory hallucinations - his brain would tell him things, mostly negative. Sometimes, however, these were more severe; such as stabbing mom. He knows right from wrong, & is just terrified when he tells me about the "talk". When things with his PANDAS got really bad, he began having visual hallucinations - seeing spider monsters crawl up into the ceiling; seeing friends with their heads off their body. Since he has had IVIG, most of these symptoms have disappeared - except for the occasional brain talk. Yet it hasn't been as bad as it was.
I think this behavior is more common than one might think, in PANDAS patients. It's not something you really want to discuss with anyone, as they look at you & your child as if something is drastically wrong with him. My best answer is that I comfort him & let him know I believe in him & what he is telling me.