Is there any proof that he’s not actually an alien living in a CIA agents attic in Northern Virginia?

You are mistaken, that is a myth.

Why is that an issue?

What’s the point of worrying about it. It’s inevitable, and when it happens you’ll not care because you won’t be able to. So what does it matter

It used to be, now it’s just bragging about how big your truck is, or how much beer you drink, or how good your wife’s ass looks in jeans.