Indeed you cannot have a chapter that is all black. The sleep chapter with a driving force of a fantastical dream is the perfect insertion reminding us of Ledd's necessity to sleep, especially as he needs to fight back the fever. Deeply thought out quote you have shared also by Kubrick, we indeed need to supply our own light, not only for ourselves, but for those around us still blindly searching in the darkness, unaware of their own ability to become a beacon of hope for themselves and others also. :)
One thing I forgot to mention in my previous reply is about the whispering. In the real world, Zepp often mutters some indecipherable chatter of his own from time to time, much like how babies are. That's my inspiration for the whispers. He feels like he's getting away with it, but really though it's just because others don't have a clue what he's saying. Kinda like how Bruce Willis didn't know he was a ghost in Sixth Sense haha (oops spoiler!)
I thought that quote really captured the chapter perfectly, and I'm glad that you agree :D