He heard Naruto's breathing stop a total of four times during those eighteen days in hospital.
Each time Kakashi's eyes immediately flew open, wide with fear and horror and no you can't die please you've got to live you've got to live—
He closed his eyes, leaning half-sprawled on the blond's bed (no one asked him to move, no one dared) but didn't let himself fall asleep even once for he was still waiting, waiting, waiting...
And on the eighteenth day Naruto's breath hitched one last time and Kakashi was ready to start shaking him in panic when he stared straight into tired, half-open blue eyes and realised – he's finally awake.
"Ka...kashi? You're... kinda going to squish me if you don't get off..."
That was the first thing he heard.
When the other man still did not move after half-pouncing onto him in relief, Naruto peered over carefully and then smiled in exasperated amusement.
He sort-of managed to budge over a little, trying to give Kakashi more space, but the other man was already asleep anyway...
He sighed, still sleepy.
...And it really was quite comfortable...
Which was mostly why when Sakura stormed in later, yelling "You woke up and you freaking didn't tell us?" he just shrugged and snuggled closer, trying to convince his startled bolster to stay.