What would (A) do if (B) just..asked something like that at random? They'd try and pass it off as a delusion or, some kind of joke obviously, they were pretty close after all so, they didn't want to humour the thought. After that, (B) starts getting into more and more trouble, getting shoved and almost falling down the stairs, getting a really bad cut when they tried making food. What do you think (A) would do about it?
That's really it, I tried to keep it open since, there's a lot you could do with this in my opinion😅 we can talk it over in the comments.