Sora appreciated Riku's effort, but he was worried about Riku now. He knew he needed sleep, and be ready for tomorrow morning, but he wanted Riku to go to sleep, too. At least it was warm, and comfortable. It wasn't until Tidus finally turned his light off and went to bed that Sora was able to fully settle down, though.
He tried to think of anything but the crash. His thoughts kept going back to his parents now though and how suddenly, oh how he missed them. Half awake, half asleep, he could be heard hmmmming a tune quietly. The same tune his Father had taught him when he was just a little boy, the one that promised he'd be back soon, and that they'd be close, even from far away. It was finally able to put him to sleep eventually.