In this fanfiction, the Chaotix detective agency could also play a role in taking care of Sonic. Vector might not be the best at medical stuff, but he could use his detective skills to find out the source of Sonic's illness. Espio could use his stealth to keep an eye on Sonic's surroundings, and Charmy could keep Sonic's spirits up with his energetic personality.
One possible plot could be that Sonic catches a strange virus that slows down his super speed. His friends like Tails and Knuckles would then have to find a cure while protecting Sonic from his enemies who might see this as an opportunity to attack.
Her friends could take care of her. For instance, Yuki might bring her some herbal tea that he made himself, believing it would help with her illness.
Thor could be one of the first to take care of Loki. Despite their differences, Thor still cares about his brother. He would use his strength to protect Loki from any threats while Loki is sick and might even search for rare remedies.
Gwen could also take care of Ben. As his cousin, she would be worried about him. She might use her magic to try and ease his symptoms or find a cure. She would probably make him some soup and keep him company while he's sick.
His best friend could be the one to take care of him. This friend would stay by his side, make sure he takes his medicine on time, and keep him company while he's sick.
It could be Dr. Eggman. He's always been after Sonic and trying to defeat him. Experimenting on Sonic could be his new way to find Sonic's weaknesses or to gain his powers for himself.
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.
Sango could also take care of Kagome. As a strong and kind - hearted woman, she would know how to nurse Kagome back to health. She might use her knowledge of herbs and remedies to make Kagome feel better. Plus, she would offer emotional support to Kagome during her illness.
The world would likely be in chaos. Sonic is often the main defender against villains like Dr. Eggman. Without him, Eggman could easily start taking over cities and enslaving the population. His friends would also be in a state of shock and grief, which could temporarily paralyze their ability to act.
Mr. Burns might try to take care of him. Despite their strange relationship, Burns could feel some sense of responsibility or concern for his loyal assistant.