[Okay, maybe he is still terrible with kids. They were talking fine earlier and it feels...off, now. Bleh. Maybe he should let it be, considering bringing it up may make things only more awkward.]

Thanks. I'm just...I would prefer if we confided in each other as soon as possible. Make sure neither of us thinks of going along with it.

[There's a chance the motive may not even be that big or important for either of them, but he'd prefer to make sure.]