Derek considers brushing it off and changing the subject, but they are friends, he supposes, and Castiel is just honest and deadpan enough that Derek doesn't think it would be awful to be a little honest himself. Castiel isn't the type to use someone's feelings against them, and Derek doesn't think he'd find him weak for saying what he feels. His friendship with Castiel is an interesting one, and Derek finds that he enjoys navigating it.

"It's my first Christmas without my big sister," Derek finally says, shrugging his shoulders a bit. "I was at the store and started grabbing things she liked without realizing it, and it sort of hit me all at once. I literally have no family left."

It sounds a bit pathetic coming out of his mouth, all quiet and sad, but it's the truth. "It kind of overwhelmed me, so I came out here."