I don't think he's simply "dumb". My guess is a combination of different things that makes him especially vulnerable to go "all in" on certain things. Whether that thing is Elon, Tesla, "woke mind virus" or whatever flavor of the month/quarter/year. There could be something clinically diagnosable, but I'd also just guess that typical combo of socially awkward, friendless, involuntary celibate, whose main connections and foundation are rooted online. The type that are simultaneously vulnerable and made victims by everybody, yet find strength and community in who they blame/hate.
Pretty typical alt-right profile and ripe for radicalization.
That said, maybe he's a completely normal guy, two kids, wife and rich as the rest of us and this is all just an elaborate troll job to see how convincing of a personality he can play?