[Hinata realizes pretty quickly that Kohaku is hurting over this. It might not be a deep, agonizing pain, but there's a regret and bitterness that he can't help but notice.]

...My best friend disappeared about a week ago, now. [He won't draw attention to Kohaku's struggle, it's just not how he is. Maybe expressing empathy in a roundabout way like this could help.] So... I kind of know how you feel. I never thought Otonashi would ever be ready to leave, h-haha...

[The laugh is noticeably forced, and weak. He just hasn't had the energy to pretend lately.] ...That's why Yurippe started the SSS, you know. We... we want to fight this.