Responses

The situation is so fucked up, but we do gotta remember that MC was transported into that body/world without consent so technically that's not really 'his' childhood best friend. Though I agree he should've had more manners and treated him better than he did. I just understood why he wouldn't have as much attachment. I think he has some intense imposter syndrome and fled post graduation to get away from the family and friends that remind him that he doesn't belong in that world - and the fact that he's losing his original memories was probably driving him insane
Smack him across the face ( ̄へ ̄)
Who the fuck are you to treat his childhood friend like that?