He’s a child playing pretend. Take this quote and imagine it’s from a 10 year old kid that then goes on to explain how their favorite superhero can breathe in space.
Like he said, he hasn't changed much since he was 5. But it's not entirely on him: when my daughter says something like that, I play along for a bit but afterwards I explain to her why it is impossible. When you're constantly surrounded by sycophants, there's no one to call your bullshit out and soon you're convinced you're the smartest person alive.