Duo, he just reads the book by looking at scribbles and understanding them!
Maybe he's blind and has to read via braille. Or maybe it's written in Danish and he doesn't understand a word :p
I understood it as "How the hell did he get his hands on your book/diary?!"
Well... Maybe he's just sitting, or lying down in bed, of even reading standing XD
Does this really mean anything in Danish? It's a very odd question in English.
Depends on the context.
Maybe he needs those red and blue 3d glasses