Of course.

[He smiles. Is that in response to the "be subtle" or the "have you done this sort of thing"?]

It would be best to ask if anyone's noticed anything strange, or any changes in someone they know. And if they're the person who's changed, their reaction will probably give them away. Most people aren't very good at hiding things.

[He's walking an edge himself there, but it's probably fine. Probably.]