Well, the motion is inoccuous enough that it doesn't really matter that Otoha doesn't know how to offer a hug- Emporio is, after a few moments, taking it as he shakes.

And apparently, given that he's quietly just nodding into the motion and sniffling, he needed it. "Yeah. ...Y...yeah. I... ...I know a lot of people on the train want to go home but... ...I'm just glad to be here... ...I'm... ...I want to stay here, even if it means I have to say goodbye to everyone else and meet others instead..."