There are indeed. In some fanfics, the Avengers' reactions can be quite humorous. They might make jokes about Tony's self - destructing suits or his attempts at flirting. Other fanfics might take a more serious approach and look at how the events of 'Iron Man 3' affect the Avengers' relationships with Tony and each other, like how it could create trust issues or bring them closer together.
Some characters might be offended. If the fanfiction distorts their personalities too much. For example, if it makes Happy Hogan seem cowardly when he is actually brave in the original story. He might not like this misrepresentation at all. However, others like Nick Fury might just take it in stride and see it as part of the popularity of the Iron Man franchise.
Captain America would likely try to be the voice of reason. He'd approach Tony with empathy, trying to understand what's going on in his head and find a way to bring him back to his senses. He might also try to keep the other Avengers calm and focused on helping Tony rather than seeing him as a threat immediately.
Perhaps he freezes for a moment. The shock of seeing Pepper pass out might be so great that he's initially stunned. But then he quickly regains his composure and uses his scientific knowledge and resources to figure out what's wrong and how to help her.
They could get emotional. Iron Man has been through a lot, and a fanfic might explore his emotional journey in more depth. The Avengers, who have fought alongside him, would likely be affected by this. They might remember the times they shared with him, the battles they fought together, and this could strengthen their bond as a team, even if it's just based on the fanfic's version of his story.
The Avengers would likely be filled with rage. Captain America, for instance, would immediately charge at Thanos, not caring about the danger. His sense of justice and loyalty to his friend would drive him to seek revenge right away.
The Avengers would also have to adjust. They've come to rely on Iron Man's technology and his combat skills. His departure could create a power vacuum within the team. For instance, they might struggle to come up with new strategies in battles without his innovative thinking. And his friends like Rhodey and Happy would be worried about him, wondering if he's made the right decision.
Tony Stark would likely be extremely worried and protective. He'd probably drop everything he was doing to be by Pepper's side, using all his resources and technology to ensure she gets the best medical care. He might also feel guilty, thinking that his Iron Man activities put her in danger.
Well, Howard Stark might have a range of reactions. He could be in awe of the advancements, or he might feel a bit left behind. Maybe he'd also have some fatherly pride and a desire to have been more involved.