I honestly don't know what he can or can't pick up on, because the supernatural beings he comes across in the show are all ones he knows already. But he does at least seem to know that they're there, and how to find them, so that's something.

He's not an empath as such, but he can heighten desire (of any sort), and get people to admit their deepest desires with a single question, but that ability doesn't seem to work on his fellow celestials, so it would be up to you if it works on her.