In the fanfiction, perhaps there is a new threat that is specifically targeting his powers. His powers could be malfunctioning, which is a big deal for him as his powers are a major part of who he is. This malfunction could cause him physical pain and exhaustion, ultimately leading to his collapse. It could also be that he has been poisoned or affected by some sort of kryptonite - like substance in the story that weakens him to the point of collapsing.
One possible reason could be overexertion. Peter Parker is often depicted as taking on a lot of responsibilities both as Spider - Man and as an Avenger. He might be pushing himself too hard in a fight or during a mission, leading to a collapse. Another reason could be some sort of external attack that affects his physical or mental state, like a new type of villain's weapon that drains his energy.
Well, it could be due to an internal conflict. Maybe he has been struggling with his identity as Peter Parker and Spider - Man for a long time in the fanfiction. This inner turmoil could build up and finally cause him to collapse. Also, it might be related to his relationships. If something bad happens to his friends or loved ones in the Avengers, it could be such a shock that his body and mind can't handle it and he collapses.
The other Avengers would likely be very concerned. They might immediately stop whatever they are doing to tend to him. For example, Tony Stark could use his technology to try and figure out what's wrong with Peter. Captain America would probably be the one to keep everyone calm and organized while they figure out a plan to help Peter.
Peter could rely on his own inner strength. He has a strong moral compass, so he might use that to remind himself that the Avengers' actions are wrong, not his. And then he could focus on using his Spider - Man skills to prove his innocence or protect himself.
The Green Goblin could be a main antagonist. He's known for causing chaos in New York City, and a building collapse would be right up his alley. He could be targeting the building for some strategic reason, like trying to get to Peter Parker or to create general mayhem.
One possible reason could be that Morgan gets more attention from Tony Stark. Peter Parker sees Tony as a mentor and father figure, and if Morgan is getting all the love and focus from Tony, it might make Peter jealous. For example, if Tony is spending more time teaching Morgan new things or just being with her while Peter feels left out.
Peter might get invited to the Avengers' headquarters. There, he could see all their cool gadgets and technology. He would be like a kid in a candy store. The Avengers could ask him for advice on how to deal with street - level threats, since he has more experience in that area. Peter would be really happy to contribute and feel like he's part of the team.
Perhaps Peter's sickness is a result of his overuse of his powers. The Avengers, especially Tony Stark, feel responsible. They start by quarantining Peter in the Avengers Tower. Then, they call in all their medical and scientific resources. They might discover that the only way to heal him is for Peter to temporarily give up his powers, which would be a huge struggle for him.
If Peter Parker joins the Avengers in fanfiction, it would change the team dynamics significantly. Peter is used to operating on his own in Queens, but with the Avengers, he'd have to learn to work as part of a much larger and more powerful team. He could introduce the Avengers to his street - level knowledge, which might be useful when dealing with villains who operate in the shadows. His relationship with Aunt May could also play a role, as the Avengers might need to protect her from any potential threats. Plus, his growth as a hero would be accelerated by being around such experienced and powerful teammates.
One scenario could be that the Avengers are facing a new threat that requires Peter's special skills. His ability to stick to walls and his enhanced strength could be crucial. Peter might also introduce a sense of youthful enthusiasm to the group. He could crack jokes during tense situations, which at first annoys some of the Avengers but later they come to appreciate it as a way to lighten the mood.
In this fanfiction, Peter Parker might show off his amazing spider - abilities to the Avengers. Maybe he'll swing around the Avengers Tower impressing everyone.
Tony Stark might immediately rush to his side and start scanning him with his high - tech gadgets to find out what's wrong. He'd be worried as he sees Peter as a sort of protege. Captain America would probably be more of a calming presence, trying to keep everyone else from panicking while waiting for medical help if needed.