Olaf would try to make Anna laugh. He would tell his silly jokes and do his goofy dances. He would also try to keep Anna warm with his carrot nose. He might even build a small snowman inside the room to keep Anna company when everyone else is busy.
His friends would most likely be very concerned. They would probably bring him things like food and medicine. TK might pray for his quick recovery.
His other friends like Shikamaru would think of the most practical solutions. He might calculate the risks of continuing the mission with a sick Naruto and come up with a plan. Maybe he'd suggest splitting the group, with some staying to take care of Naruto and others proceeding with the mission - related tasks that can't be postponed.
Raven would probably be the first to sense that something was wrong with Beast Boy. She'd be quiet about it at first, but she'd start keeping a closer eye on him. Maybe she'd make him some herbal tea that she believes has healing properties.
She might be taken care of by Elsa. Elsa would use her powers to cool Anna down if she has a fever, and bring her some ice - made treats to cheer her up.
Elsa would be extremely worried and angry. She would probably use her powers without hesitation to find Anna. Kristoff would be very determined to rescue Anna. He loves her and would do anything to get her back. Olaf might not fully understand the situation at first but would still try to help, like using his cheerfulness to keep Anna's spirits up while she's kidnapped.
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, initially, her friends would be stunned. Harry would be at a loss for words. He'd be thinking about all the times they had together and how Hermione's appearance was part of who she was. Ron would probably blurt out something insensitive in his shock. But as time passed, Harry would start to see that Hermione was still the same person inside. Ron would slowly come around too, especially when he realized that Hermione's decision was more complex than he first thought. Ginny would be the one to really help Hermione feel accepted, reminding her that her true self was more important than her new look.
Her friends would likely be very shocked and worried. Some might rush to the hospital immediately and stay by her side, constantly checking on her condition. For example, her best friend might be in tears and refuse to leave until they know Bella is out of danger.
His friends would most likely be very worried. They would gather around him, trying to figure out what was wrong. Percy might use his water powers to cool Leo down if he had a fever. Annabeth would be researching in the library, looking for any information on demigod illnesses. Hazel could use her powers to sense if there was any dark magic involved in Leo's sickness.
In most 'Naruto gets sick' fanfics, his friends are very concerned. For example, Sakura will immediately start using her medical skills to diagnose and treat him. Sasuke, although he may not show it outwardly as much, will stay by Naruto's side and keep a watchful eye. Shikamaru might come up with plans to make Naruto more comfortable during his illness. And Hinata, she would be really worried and would probably bring Naruto some home - cooked food to help him regain his strength.