One possible reason could be the stress of his ninja duties. He has so many missions and responsibilities that his mind is constantly racing, making it hard to relax and fall asleep.
Yamato might show his concern by constantly checking on Naruto's condition. He could be seen sitting by Naruto's bedside, feeling his forehead for fever regularly.
One classic can't - sleep story is 'The Three Little Pigs'. The story of the three little pigs building their houses, one of straw, one of sticks, and one of bricks, and the big bad wolf trying to blow them down is engaging. It has enough suspense and a happy ending that can soothe your mind. Another could be 'Goldilocks and the Three Bears'. The idea of Goldilocks exploring the bears' house and getting into all sorts of situations is both interesting and can take your mind off your sleeplessness.
The 'Can't Sleep with Tea Concubine' emoji was a popular emoji on the Internet. It was used to express the situation of not being able to sleep after drinking Tea Concubine. This emoji was very popular among the young ladies. It was used to express the feeling of insomnia humorously. Although there was no specific picture of the emoji in the search results, it was certain that the emoji was used to describe the insomnia after drinking the tea.
Yamato might first try to use his calm and steady presence to soothe Naruto. He could place a hand on Naruto's shoulder and speak in a gentle voice, telling him to take deep breaths.
Yamato might first be a bit shocked. But then he'd probably try to calm Naruto down. He could use his wood - style jutsu to create a peaceful environment, like making a small forest around them to soothe Naruto.
Some Naruto fan forums may also be a great place to find such fanfictions. These forums usually have dedicated sections for fanfiction. You can browse through the threads or create a new one asking for 'Naruto has Yamato' fanfictions. Just be sure to follow the rules of the forum while doing so.
Some Naruto - related forums also share fanfiction. These are often communities of Naruto fans who are passionate about the series and might create or recommend good Naruto and Yamato fanfiction. However, the quantity might be more limited compared to the big fanfiction platforms.
In a fanfiction, Naruto, Yamato, and the katana could be part of a quest. For example, they are on a mission to return the katana to its rightful place. Along the way, they face many enemies and Naruto uses his unique skills while Yamato uses his wood - style jutsu to protect the katana and each other.
I have a novel that I can recommend to you. It's called " Elf: I'm the King of Heaven by Taking Medicine." This book described a man who couldn't sleep every day and had to rely on medicine to fall asleep, but a woman's voice could help him fall asleep. This story combined the elements of a drug refiner and a trainer, giving the readers a magical experience.