One night at home, Souta realizes that Nazuna is now as tall as he is, depressed, he begs Poplar to act as his little sister for a day to cheer him up. This leads to everyone thinking he’s about to go crazy. This attention makes Mahiru jealous, so Hiroomi tells her to show Souta a picture of her when she was little, which causes Souta to say she’s cute, something she records on her phone and plays over and over. Kirio then shows up at the restaurant, and Hiroomi goes to great lengths to try to prevent him from finding Aoi.
Normally when Hiroomi hides information that would clear a situation up, he’s just doing it to see how things play out, partly because it amuses him, and partly because I think it helps him learn about what everyone else does and thinks. But in this case, I’m not sure if it’s the case, or if it is, he’s willing to go to some rather great lengths to hide Aoi. It doesn’t seem like he has any specific knowledge about Aoi’s situation, but I suppose part of it is that he feels that Aoi ran away for a reason.
Meanwhile, it really does seem like Souta is about to have some sort of breakdown. His last hold to being “big” was that he was taller than Nazuna, and now he’s lost that. Maybe having a picture of Mahiru when she was little will start softening his view toward her. Or at least one can hope, I suppose.