Ploegy
"The arcana is the means by which all is revealed"
Thing is Sora probably doesn’t outright grieve. He’s going to be desperately trying to use his Power of Waking to cheat death. He could probably succeed in that though maybe not since I have early KH2 Sora and all that kind of stuff is KH3 Sora. But imagine a scenario where their friend is killed and Sora does successfully trigger the Power of Waking. Basically he would be saving that person but in exchange for saving them he disappears, being punished for abusing his power in ways he shouldn’t be. Yes he’s alive but he’d trapped far away and would presumingly be dead to everyone because they just watched him fade from existence and all (and well that’s entering KH4 territory which we don’t know what happens lol)Pit would probably be standing there silently, his bangs covering his eyes and making him seem uncharacteristically cold. He had to do it, not just out of mercy for their friend, but to save Sora's life; he was going to keep futilely trying to save them until he died. Pit couldn't allow that. Unable to say anything, he leaves Sora to grieve. There is still a job to be done and a world to save. I think such an event would drastically change how one views the other.
If it was Dark Pit, I can see him staring straight into Sora's eyes and saying something along the lines of, "I'd expect you to do the same for me," then walk off.
Now I think of this happening and the other revives still corrupted making it so they have to be killed again and the group lost Sora in the process because he quite literally gave himself up to bring them back. Yep that’s not a depressing thought at all. I didn’t need to wake up at 5am and think of this hahaha