I CAN IMAGINE SO MANY REACTIONS I could imagine him running over to him and reentacting the "oh my dear friend, I missed you!!" scene but quieter and while hugging him instead of taking his hands.. however, maybe he'd feel even more trapped than he already did before.. he already experienced grief from losing him, he knows Fyodor's death wouldn't free him, and despite having experienced that, he's back, as if nothing happened?? I don't think he'd have a stable reaction to that.. or maybe he'd even react similarly to how he did when Fyodor died.. quiet.. sombre.. needing to process whatever is going on..

but my absolute favorite hc that someone presented to me a few days ago is him thinking that he's hallucinating Fyodor being alive and feeling even more trapped because of that..

no matter what, he will never be free from his feelings for Fyodor..

BUT SERIOUSLY there are so many ways I think he could react, I can't pinpoint a single possibility.. but that's what makes his character so great.. he's unpredictable..