During the attack by gargoyles after rescuing Serana, poor Faendal was killed. I didn't want this, so I went back to a saved game just before finding Serana, loaded us up on loot while going back out of Dimhollow Crypt and took it home, returned to Dimhollow Crypt, asked Faendal to wait at the entrance, and rescued Serana alone.Â
After taking Serana home to Castle Volkihar and refusing the offer to become a vampire, I eventually returned to Dimhollow Crypt to retrieve Faendal. He wasn't there. Using the console command player.moveto (RefID for Faendal) took me back to the main hall of Castle Volkihar, where he was waiting.
I don't understand how he got there. Is this a bug?