[Atsushi may not have any idea what's wrong, exactly, but it's clear that something is off. He's not always capable of drawing the right conclusions, but he's always sensitive to changes in people's (and, apparently, puppers') attitudes.]

... Are you all right?

[No, something is definitely wrong.]

If it's about him not growing, please don't worry about it! I think he's just meant to stay small - look, just like some dog breeds are smaller than others!