He's been sleeping earlier and earlier, lately.
It's not really what you would expect from him, to head home, finish whatever homework he feels is totally necessary and then crawl into bed. But his dreams have been so vivid, lately, so exciting, and there's definitely nothing in the waking world that's competing right now. He doesn't really see the point of being awake anymore.
He shuts the shades as tightly as he can to block out the fading sunset, rolls into bed without bothering to change, and – more easily than he should logically be able to, given how much he's been sleeping and how early in the night it is – drops off.