[Momo grins encouragingly, like it's fine that he's been here that long, but also this is Momo and lying about how he feels about things is basically his m.o. Considering Yuki's reactions to loss, though, ensuring how things back home worked while he was here was actually one of the first things he confirmed upon arriving here.]

I've heard things kinda...pause? Or something, while I'm here. Or I go back to the same time I left or something like that. But it's nice to have confirmation...what's the last thing that happened before you came here?

[He's curious, now - he came from when things were ramping up towards Black or White, but he does know Yuki arrived in a performance outfit while Momo arrived in civvies, which implies Yuki's from at least a minimally different point in time than he is. If Riku's from any earlier or any later than him, it'd be basically complete confirmation what he was told about time passage was true.]