Luke's knowledge of Stiles is fairly limited, but he knows enough to keep his mouth shut. Maybe at the end of this all Derek will resent that he didn't tell him, but he can accept that in return for Derek's happiness. Even if it doesn't last, he should at least be allowed to have this for a little while. Being sixteen all over again is bound to be strange enough without Luke complicating things by telling him how he'd lost the love of his life not all that long ago.

And so he doesn't. He'll face the consequences of that if he has to.

"You don't have to go back there," he says. "I mean, we should probably go get your cat and that purple thing, but if you want to stay here until everything's back to normal, I have the room." He has two spare rooms, actually, and while neither of them are particularly big, it would be nice to have someone in one of them.