"It really is." And it really is hard to make Alec think something is odd.

Alec is no telepath, he's an empath and not a very strong one at that. He could possibly keep Nathan out of his head, but there's no way he could get into Nathan's shielded mind. And while Alec could cheat and look at it through just the strands of reality, it's fairly rude so he tries to do it by observation.

"Ah. I've talked to some people and when they say world they lived it, it's because their old world was destroyed. May I ask why you moved?"