There could be a plot development where the Weasleys' discovery of Harry's abuse leads to a rift in the wizarding community. Some might not believe Harry was abused or might try to cover it up. The Weasleys would then have to fight against this disbelief and secrecy. They could also form alliances with other families or characters who believe Harry. In the meantime, Harry might start to develop new magical abilities as a result of the love and support he gets from the Weasleys. This could be a turning point in his growth as a wizard, as he learns to use his magic in a more positive and confident way.
One possible plot development could be that Draco tries to expose the abuser. He might gather evidence secretly and present it to the right authorities at Hogwarts.
One possible plot development could be that Snape initially struggles with his feelings towards Harry. He has his own past grudges against James Potter, but as he sees the extent of Harry's abuse, his protective instincts kick in. He might start teaching Harry advanced magic in secret, away from the prying eyes of the other Hogwarts staff and students, especially those who might be skeptical of Snape's motives.
Perhaps Harry sues the Weasleys because he believes they misused some of his fame for their own financial gain. For example, they might have used his name to promote their joke shop without his permission. And Harry, being fed up with this exploitation, decides to sue them to set things straight.
Well, one plot development could be that Voldemort decides to use Harry's abused state to turn him against the Order of the Phoenix. He might see it as an opportunity to corrupt Harry further.
One plot development could be Lucius using this information to try and manipulate Harry. He might offer Harry a way out of his abusive situation in exchange for Harry's loyalty or some other form of service. For example, he could ask Harry to spy on Dumbledore for him.
One possible plot development could be that his friends are left to pick up the pieces. They might struggle with grief and guilt, thinking they could have saved him. Another could be that Voldemort finally takes over completely without Harry to oppose him, leading to a dark reign over the wizarding world.
Well, one possible plot development could be that the Malfoys, in rescuing Harry, have a change of heart towards the whole fight against Voldemort. Maybe they start to see the error of their ways and side with Harry more openly. For example, they could use their influence in the wizarding world to help Harry gather more allies.
One possible plot development is that the gods gather to hold a trial for the abuser. They would bring in witnesses, and Percy would have to testify about what happened to him. This would be a very emotional and intense scene.
Maybe in that fanfic, there are misunderstandings between Harry and the Weasleys. For example, they might have had an argument over something like magic use or family values that led Harry to dislike them.
The Weasleys are likely to be horrified. They are a warm - hearted family. Mrs. Weasley might immediately take on a motherly role towards Harry, perhaps making him his favorite foods and fussing over him. Mr. Weasley could become very protective, ensuring that Harry is safe from any further harm. The siblings, like Ron, might be angry that Harry had to endure such abuse and vow to always have his back.