It was extremely dark, and it made Kili nervous. The mountain kingdom of Erebor was massive and spacious, amplifying any and all sounds. Coupling that with the fact that he now had vivid flashbacks of the battle to reclaim the mountain assured that Kili barely slept.
So, with no other choice, Kili lay in his bed and sobbed quietly, so as not to wake his older brother.
Thorin was making his way to his own chambers when he heard the sound of quiet, distraught cries echoing off of the walls. Walking to the doorway of his nephews' room, he saw the silhouette of his youngest boy shaking.
"Kili," Thorin whispered, noticing his young nephew's obvious distress and making his way over to sit on the edge of the bed, "what's wrong, lad?"
"I-I can't sleep." Kili answered, "It's t-too dark. A-and I keep having bad dreams a-about the b-battle."
"It is very dark here, isn't it?" Thorin murmured, shifting to rest his back against the headboard before gently taking Kili into his arms.
"Much darker than it was back home," Kili murmured, reaching out and curling his fingers into his uncle's tunic.
Thorin gently stroked a hand over Kili's hair, wincing as he felt the distinct texture of blood on his hands, and heard Kili let out a pained whimper.
"Oh lad, you opened your stitches," Thorin sighed as he helped Kili to sit up. "Come, let's get you cleaned up, so we can both get some sleep."
Standing up, Thorin lifted his nephew into his arms and settled the boy on his hip before moving out into the hallway to assess the damage.
Thankfully, Kili had not ripped his stitches and the blood was only a result of a small cut on his scalp that had reopened. Soon, Thorin had the boy cleaned up and settled against his chest on the bed, along with his brother.