Sounds like he might have just been drunk.
While at Uni staying in halls, a mate of mine was staying over for a drunken night out. We got back fine, and he fell asleep in his boxer shorts on a chair in the corner.
In the middle of the night, drunken friend heads out to the toilet before coming back and feeling a little cold. He managed to find jeans, t shirt etc on the floor and fell back asleep in the chair.
Pity it wasn’t my room. 🙂
He woke up in the morning to find a very scared guy hiding under his duvet asking wtf he was up to. My friend made things worse by thinking it was some kind of practical joke and telling him to shut up before trying to go back to sleep. As he started to realise what was going on, he then tried to leave. Guy starts shouting he’s nicking his clothes, wallet etc and an argument breaks out before my friend realises that he IS wearing the guys clothes and they are far too small. Cue lots of apologetic backtracking, he then stripped off and not wanting to nick his boxer shorts, stripped stark naked before setting off to find my actual room. I think he spent about half an hour trying to find my room, before I got woken up by the banging. He didn’t have the heart to go back and ask for his boxers, and didn’t even know what room he had been in.
The funniest thing was, a few years later, a group of us including the guy involved above were in a pub for a quite drink. Another friend turned up with a new girlfriend who after a while started to tell the above story, only from the other perspective. Turned out she knew the poor guy above who had told his friends the story, who didn’t believe him. Only shred of evidence he had were a dirty pair of boxer shorts.