Spider-Man: No Way Home was a powerful way to end a trilogy surrounding the wall-crawler, but it also laid the groundwork for a future where things could change forever for a version of Peter Parker forced to mature faster than he'd have liked. However, the same could be said for Peter's closest friends, like Ned Leeds, who started the series out as the "guy in the chair" but was set up to have his own level of importance, and one theory showed how a variant of Peter may have saved Ned without having to leave his chair.
In the film, the appearance of the Multiverse gave Peter Parker an opportunity to interact with variants of himself played by Tobey Maguire (Peter 2) and Andrew Garfield (Peter 3). While they were only in the film for the third act, both Peters made considerable use of their screen time to offer Peter lifelong lessons and inspiration for his future, but one thing that had always plagued the life of a Peter Parker was a doomed friendship between him and those closest to him. However, thanks to Reddit theorist ddsling1197, it's been explained that Peter 2 likely used his own life to terrify Ned in a way that would keep him from turning evil.
In all the Spider-Man films, Peter's closest friend, Harry Osborn, was seemingly destined to become the Green Goblin and tarnish a once cherished friendship. According to the theory, when Ned asked Peter 2 about his past and his friends, Peter chose his words carefully and explained that Harry had tried to kill him, then died in his arms. For many fans of the franchise, they knew there was much more that went into their friendship that Peter 2 willingly omitted, but the reason for this was because his goal was instead to break the cycle by scaring Ned straight.
While the theory gave a largely surface-level explanation of this, that's all that's needed to dive deeper into the realization that Peter 2 knew exactly what he was doing. In fact, it explained that Peter 2 already knew that Ned had magical abilities, so the groundwork was already being laid for a friend to become a potential foe. As a result, Peter 2 made the choices he did in ensuring Ned would never try to kill his friend. Also, being that Peter 2 was always a man of few words, it wasn't entirely out of character to give a simplified explanation for his relationship with Harry and how it ended.
By omitting Harry's betrayal and sacrifice, it showed to Ned that Harry was a person who started out as a great friend that eventually turned evil and possibly was killed by Peter. Plus, since Peter 3 didn't have a chance to share his experience to Ned, it was perfect for Peter 2 to take the reins on the explanation. Then, when the time came for Ned to tell Peter he wouldn't betray him, Peter 2 and 3 knew he meant it, hence the pat on Ned's shoulder from Peter 3.
This theory is a unique way to enhance the viewing experience; however, what's even more interesting is the fact that it also shows how important experience can be. Peter 2 was the oldest of the others and had seen the most. Therefore, he knew that sometimes less is more. Plus, having to see a version of Peter who lost everything vs. one who still has things to lose, Peter 2 knew saving his friend is most important. Even though Ned ultimately forgot about Peter, there were still glimmers of the truth hidden beneath the surface of Peter's friends, and because of this, it's likely Ned would never betray Peter even if he didn't realize it.