There's a fanfic called 'Sickly Harry's Struggles'. In this story, Harry gets a strange sickness that affects his magic. It's interesting as it delves into how he tries to cope with it while still facing the challenges at Hogwarts. It also shows the different potions and spells the school tries to use to heal him.
They're popular because it shows a different side of Harry. Usually, he's seen as the hero, but when he's sick, he's vulnerable. People like to see how the other characters react to this vulnerable Harry.
Well, there's 'Harry's Malady'. It's a fanfic that focuses on a magical sickness that only affects those with a special type of magic, like Harry. It shows how isolated he feels at first, but then how the wizarding community comes together to try and help. And 'The Sickened Seeker' is a good one too. In this story, Harry's sickness is related to his Quidditch skills. It's a unique take on a sick Harry Potter fanfic as it combines his love for the sport with the struggle of dealing with an illness that affects his performance.
One common theme is the idea of friendship. When Harry is sick in fanfictions, his friends like Hermione and Ron often come to his aid. Another theme is the mystery of the illness. It could be a new dark magic - induced sickness that no one has seen before.
One great 'Harry gets sick' fanfiction could be 'Under the Weather'. In it, Harry catches a strange magical illness that has everyone worried. It's a really interesting take on how the Hogwarts staff and his friends react to his weakened state.
In addition to his family and friends, the medical ninja in the village would be involved. They would be the ones to accurately diagnose Boruto's condition. Shizune, for example, could come and check on him, using her vast medical knowledge. And the other young medical ninjas might learn from this case, as Boruto's illness could be something new or unusual, so they would be eager to assist and gain experience while taking care of him.
Well, Harry could marry one of the veelas. Given their beauty and allure, it would add an interesting dynamic to the story. Their relationship could involve Harry having to deal with the jealousy of other wizards and also the cultural differences of the veelas. Or he could marry a descendant of one of the founders of Hogwarts. This would tie in a lot of Hogwarts history into their relationship, and their wedding could be a grand event that unites different factions within the wizarding community who have ties to the founders.
Maybe Dumbledore, if he were still alive in the fanfiction. Dumbledore was highly respected and had a great influence. Knighting Harry would be a way for him to publicly recognize Harry's achievements and heroism on a grand scale.
Seth could be the one to help her. As her brother, he would be very concerned and might use his own knowledge of Fablehaven and its secrets to try and find a cure. He could also enlist the help of some of the friendly magical creatures they've befriended, like the fairies or the satyrs.
His teammates, Sasuke and Sakura, would surely be involved. Sasuke, although he may not show it as much, still cares about Naruto. He would keep an eye on Naruto's condition, and if there was any sign of danger, he would be ready to protect him. Sakura would be more hands - on with the medical care, checking his temperature, giving him medicine, and making sure he rests properly.