If I remember well, historically speaking, at some point women had their night clothes under their regular day clothes (as undergarment or something) so maybe he just took off one layer...
If I remember correctly she said that she woke up in her own bed, so I had a thought that maybe he just brought her into her room, but it may have been her roommate who changed her clothes. Either way I find your theory really cool, there are many situations where having your nightgown under your regular clothes would be pretty convenient, such as in this case.
Indeed ! But it must not feel great if you sweated all day long (⊙…⊙ )
Aaaaaaaa what is happening?? Hopefully the guy didn't change her clothes..