At first, Percy would be in disbelief. How could anyone disown his amazing mother? Once he realizes it's real, he'd be filled with a mix of emotions. Anger towards those who did it, of course. But also a sense of responsibility. He'd see it as his duty to fix this situation. He'd start reaching out to his friends in the demi - god community for help. He might even consider going against the rules or the will of some gods if it means getting his mother's family back. He'd be constantly worried about Sally's well - being during this time, and his focus would be solely on restoring her place in her family.
Percy would be extremely angry. He loves his mother deeply, and her disownment would feel like a huge injustice. He'd probably want to immediately go and confront the people who disowned her. Maybe he'd also feel guilty, thinking it's his fault as a demi - god that his mother is in this situation.
Percy might be very confused at first. He would wonder why his mother, who has always been there for him, suddenly left. He could start to question if he did something wrong. In some fanfics, he may go into a state of denial, not wanting to believe that she's really gone.
One possible plotline could be that Sally is disowned by her family for being involved with the world of the gods. Percy then has to go on a journey to find a way to restore her family's acceptance. He might face various mythological creatures and challenges along the way. Another idea could be that Sally's disownment is part of a plot by an enemy to get to Percy. So Percy has to protect his mother and also figure out who is behind this scheme. It could also be that Sally discovers a dark secret about her family that leads to her being disowned, and Percy helps her uncover the truth and clear her name.
Percy would be extremely hurt. Sally is his mother, and her betrayal would shatter his world. He might initially go into denial, not wanting to believe that she could do such a thing.
Another reaction could be that Percy is worried about Sally getting into trouble because of him. He might try to convince her to stay out of it, fearing that the abuser or those associated with the abuser could harm Sally. But at the same time, deep down, he wants her support and protection.
Percy would be completely devastated. He might go into a state of shock at first, unable to believe that Annabeth is really gone. Then he could become filled with rage, vowing to take revenge on whoever or whatever was responsible for her death.
He would likely be angry. Percy has a temper, and being betrayed by someone he thought was an ally would fuel his rage. He might lash out verbally or even physically, depending on the situation. For example, if they were in a battle together and Artemis suddenly turned on him, he would have to defend himself while also dealing with the emotional turmoil of the betrayal.
Grover would be really worried. He's always been Percy's protector in a way. He would be concerned about how this would affect Percy's life and safety. He might also try to help Percy find resources or support within the demigod community.
He may also try to figure out what went wrong. Percy is a smart demigod, and he would likely not just accept the betrayal without trying to understand the cause. So, he might start investigating, talking to other characters who might have some insight, like the other demigods or even some minor gods who are friendly to him.
Annabeth would be devastated. She and Percy have a deep connection. She might go into a state of shock at first, then be filled with a fierce determination to find out who was responsible and make them pay. She would probably also be racked with guilt, thinking she could have done something to prevent it.
Some fans might be intrigued. They could see it as an interesting exploration of 'what if' scenarios, even if it goes against the grain of the original story. However, a large number of die - hard fans would probably be quite upset as it goes against the strong bond that was built up between the two characters throughout the books.