Is Gavin being around messing with the timeline? Has he just learned that he has to go back to the past? He looks uncertain about what's happening while chilling next to the fire.
Crowley's son has been in hiding since his father whisked him away in Supernatural Season 9. It looks like Gavin has been bus hopping, but he may have been found by Sam and Dean.
Sam looks concerned that there are too many books and not enough time to read them. Or he's worried about some ghost getting the girl he's trying to protect. Either or.
Why do they call this place The Empty? It's full. It's full of sorrow and despair playing over and over again of angels and demons dreaming about their regrets. Forever.