You noticed Daisuke acting a bit off like he was upset. He was just more quiet and less optimistic and spunky like his usual self, You ask him and he answers a bit shakily

“Oh me? I’m totally good we’re all gonna be fine..!”

You pushed a little more and he paused then he broke down sobbing

“No im not fine! hiccup! I miss my mom.. like really badly…”

he started to full on sob his little heart out infront of you clearly upset over this and probably very homesick as your in space in a recked spaceship.