[moments when it's especially felt he's not the right Kim Dokja, but there is some relief in having the answer Yu Junghyeok would prefer in lieu of that.]

People in Solitary do not participate in the scenarios that occur here.
They're asleep, presumably, because it's a form of stasis to keep their monsters from continuing to overwhelm them entirely.
You can ask Jiang Yanli on Echidna or Wei Wuxian and Lan Wangji on Phoenix for details about the realm they went to where they were resting.
I'll look into getting more information where I can but for now everything's pointing to he's safe and not in danger currently.