Sketch spoilers for the comic thingy because I can't not share what's in my head. I've had this idea brewing ever since I went back to look at background art, comparing between episodes and noticed that Kakashi is sleeping on what appears to be the kitchen floor of his fathers house, even into his late teens and as a young adult. I haven't been able to let it go because surely there are more suitable spaces to sleep in in a house like that, rather than the kitchen? Does he sleep there so he can be close to the sink when he wakes up from his nightmares, needing to wash his hand? Is it because the rest of the house feels too big and full of memories to be in alone? Is it a heating issue?
This is the same floor where he sat on with Rin and Obito when he let them in to share a meal he caught and cooked himself. The moon would shine in through the same window where Obito was spying on him while he was cooking. I started thinking that Obito would also be confused about Kakashi's kitchen-sleeping habit if he happened to come back to do a bit of spying during all those lonely downtime hours when he's waiting for his big dream project to come together.
He'd notice the recurring nightmares if he bothered to come back now and then. Would he be able to see the same images Kakashi sees? He saw them when they happened, through the eye so it's not unthinkable. Either way he could probably figure it out. Would he feel Kakashi deserves to suffer like that every night or would he be like: Yeah I know mate, we're in hell, I'll fix it soon - and then give Kakashi (and himself) little samples of what his big wonderful dream could be like once all his hard work pays off? Like a treat? A way to tell himself he's on the right path? Would it be a comfort to sneak (creepily kamui swirl) into that kitchen and help his old friend through the nightmares, even though Kakashi can't be allowed to be awake enough to know?
How would it feel to whisper "I'm alive" and be close to someone warm and familiar, just for a little while?