The new agents in the team would look up to Tony and be worried about his absence. They might try to prove themselves more in his absence, hoping to make him proud when he recovers. And the whole team would generally be on edge, as Tony is an important part of their dynamic, and his sickness throws things off balance.
Abby would be all over Tony, bringing him some of her special energy drinks (even though they might not be the best for a sick person). She'd also use her skills to try and find out what's wrong with him in a more scientific way. Ducky would of course offer his medical expertise, and might even tell some long - winded stories while examining Tony to try and keep his spirits up.
Leo would likely take charge. He'd be calm on the outside but worried inside. He'd make sure Donnie gets proper rest and tries to organize the others to help. Raph might be a bit gruff at first, but he'd actually be really concerned. He might offer to get supplies or guard Donnie while he sleeps. Mikey would be the most emotional. He'd probably be constantly by Donnie's side, trying to tell him jokes to make him feel better.
The teachers, especially Aizawa, would also be worried. Aizawa might give Bakugou special permission to skip classes or training until he's recovered. He'd also keep an eye on Bakugou's progress and make sure he's taking care of himself.
Sakura, being a medical ninja, would immediately start examining Naruto. She'd be very worried and use all her skills to try and diagnose the illness. Sasuke, on the other hand, might not show his concern openly but would be constantly on edge. He might secretly look for ways to help Naruto get better. Shikamaru would probably start thinking of strategies to keep the village safe while Naruto is sick.
The other characters' reactions could vary. Some of the more hot - headed gang members might initially be impatient about Ponyboy being sick and not being able to participate in their activities. But as they see how serious it is, they would come around. The Socs, if they knew, might not care much on the surface, but there could be a few who feel a bit of sympathy, especially if they start to see Ponyboy as more than just an 'outsider'. And the girls in the story, if there are any, would probably be very motherly and bring things like soup and warm blankets for Ponyboy.
Zuma would probably offer to keep Skye company near the water, as he loves the beach. He could tell her funny stories about his underwater adventures to make her laugh. And Ryder would be in charge of making sure Skye gets proper medical attention. He'd be constantly checking on her and making sure she has everything she needs.
The village elders would also be concerned. They might start to think about the future of the village without Naruto. Some might even start looking for a temporary replacement for him as Hokage, which could cause some internal conflict in the village as not everyone would agree on who should take over.
Scott would probably be very protective. He'd do everything he can to find out what's wrong with Liam and how to cure him. Stiles might use his detective skills to figure out the cause. He'd be running around, asking questions and looking for clues.
The other characters would be very worried. Edmund, for instance, would probably feel guilty as he might think it was his fault in some way. He'd be constantly by her side, trying to make her feel better. Peter would take on a more responsible role, looking for ways to get help. He might search for a magical cure or someone who could heal Lucy.
Nya would be very worried. She'd probably stay by Jay's side as much as possible, trying to take care of him and find a way to make him better.
Ash would be extremely worried. He'd do everything he could to make Pikachu feel better, like staying up all night to take care of it. Misty might offer some practical advice, like making sure Pikachu stays warm. Brock would probably be ready to cook some special food for Pikachu to help it regain its strength.