my friend glitched

hi guys, i was wondering if you guys know how to unglitch my ffriends acc he just logged in and he was glitch the glitch is hes on the second floor and he cant see npcs only certain objects. if you could help id appreciate it.

I would tele him out of there but i got reset and cant now. what to do. Tele to slayer, walk around until u find the chain "ladder" Dont go down the steps it wont work, just go to the chain ladder and climb down.