I would go further.
I put it to you that he is most probably not dumb or "a joke" or particularly "idiotic". Even when he says things that we here would immediately flag as ignorant, he is probably intentionally covering up his actual level of cognition.
His obfuscating style of speech may be very deliberate. He misdirects, confuses and disrupts a questioner, feinting out of the path of incoming challenges, and often answers a question that is different to the one being asked. In this way, he controls a room and controls a narrative. He should not be underestimated and is a very dangerous individual, quite the psychopath actually.