Ren does not, in fact, know. But, he can guess, from the way Mona says it.

"... He cared a lot for Leblanc," Ren agrees. Even if they didn't know each other for very long, that much was clear. As much as Ren feels like Leblanc is his home, it felt a little intrusive, with the way Frog had clearly kept this version of it alive.

So weird. But, at the same time, it worked. Ren had looked forward to getting to know Frog better.

He wonders... "Do you think we can ask Igor or Lavenza about it?" Igor runs this place, after all, and while he hasn't seen her, something tells him Lavenza must be around, too.