That he has firmly, mentally, moved Zerxus into his room is reasonable. That he is now calling it Zerxus is something he'll think about, later.

Or pointedly not think about it.

All the same, they emerge at effectively the doorway, and he guides Zerxus inside. He lets go exactly enough to start taking his borrowed pajama top off. "Does this happen every time you attempt sleep?"

He's more distracted by the puzzle pieces scattered in that notebook.