Perhaps in this fanfiction, Archie gets sick because of a curse or something supernatural. Riverdale has had its fair share of strange happenings. He could have angered some sort of vengeful spirit while exploring an old part of town. His sickness would then be more than just a physical ailment but also a sign of the supernatural at work. Betty could consult her grandmother's old books for a possible remedy, while Jughead might be skeptical at first but then get drawn into the search for a way to save Archie.
The plot might involve Archie getting sick due to some sort of mystery in Riverdale. For example, there could be a strange virus going around that only affects certain people. Archie's sickness could be the starting point of an investigation. His friends, being the curious and caring bunch they are, start looking into what's causing it. This could lead to uncovering secrets in the town that were previously hidden. Also, Veronica might use her family's resources to try and find a cure for Archie.
Well, Betty will be super worried. She's always had a soft spot for Archie. She might skip her own activities to stay by his side, constantly checking his temperature and making sure he's comfortable. Jughead, on the other hand, will try to keep things light. He'll tell Archie stories about the latest strange things he's seen in Riverdale to distract him from his illness. Veronica will be more of the practical one. She'll call in doctors or specialists, using her family's influence to ensure Archie gets the best care possible. All in all, his friends will rally around him.
Well, perhaps she gets sick because of some sort of environmental factor in Riverdale. It could be related to the polluted river or some toxic gas leak. And this sickness then affects her relationships with Jughead, Archie and Veronica. She might become more withdrawn and they would have to figure out how to help her.
Maybe Sonic's friends will take care of him. They could bring him medicine and make sure he rests. For example, Tails might use his inventions to find a quick cure.
Maybe Kenichi gets sick just as a big tournament or important event is about to happen. His team has to decide whether to participate without him or wait for his recovery. This creates a lot of tension and internal conflict within the group.
Well, the plot could involve Robin's friends rallying around to take care of him. Maybe they bring him soup and keep him company while he's in bed recovering.
Well, one possible plot could be that Elsa's sickness is a magical ailment. Maybe she got it from using too much of her ice powers at once. Her sister Anna would then be worried sick and try to find a cure. She could search all over Arendelle and even beyond for someone who can help Elsa get better.
In the 'bendy gets sick fanfiction', perhaps Bendy has caught a strange illness that is affecting his ability to draw or create. His friends then embark on a journey to find a cure. They might face various obstacles along the way, like dark creatures or tricky puzzles. They'll have to use their wits and friendship to help Bendy get better.
Well, perhaps in the fanfiction, Kagome's sickness is a result of some dark magic. Her getting sick could be a part of an enemy's plan to stop her from interfering in their evil deeds. Her friends then have to not only deal with her illness but also figure out who is behind it all and stop them before it's too late.
Maybe Rigby catches a strange flu. His friends try to take care of him but keep making things worse in a comical way.
In the fanfiction, Yami could be cursed by an enemy, which makes him sick. His strength starts to fade away. His friends notice the change in him and start to investigate. They discover the curse and search for a way to break it. Along the journey, they meet various characters who either help or hinder them. Yami's condition worsens, but his friends don't give up. Eventually, they find a powerful mage who can break the curse, and Yami is cured, learning valuable lessons about the power of friendship and the importance of being vigilant against enemies.