Well, they could rely on their friends a great deal. Just like Percy has his friends at Camp Half - Blood. They could help with things like getting around, getting food, and protection. His friends might also try to find a cure or at least some way to make the paralysis less severe.
Percy could cope by relying on his friends. His friends are very resourceful and they would surely help him out. They could carry him around when needed and be his eyes and ears in dangerous situations.
Percy could use his combat skills. If the bullies physically attack him, he can defend himself without seriously harming them. He's trained at Camp Half - Blood after all. Another way is to use his wits. For example, if they mock his dyslexia, he can come up with smart comebacks about how his different way of thinking gives him an advantage.
He might use his sword skills and his ability to control water. For example, he could create shields out of water to protect himself from attacks. He would also try to find any weaknesses in his enemies. If there are any water sources in Tartarus, he could use them to his advantage, like making geysers to distract or attack his foes.
Percy could also try to use his wits and charm. He is a likable character. He might try to convince Aphrodite that he is not the right person for her. He could point out all the reasons why their marriage would not work, like their different natures and his already existing relationships and responsibilities.
He should focus on self - improvement. Maybe work on his flaws like his impulsiveness or become more reliable. Percy could also try to expand his social circle. By meeting new people, he might find someone who appreciates him for who he is. He could also throw himself into his hobbies or work. If he likes fishing, he can spend more time fishing to take his mind off the rejection and also gain a sense of accomplishment.
One idea could be that Percy is paralyzed during a battle with a new and powerful monster. His friends then have to find a way to heal him while also protecting him from further attacks. Maybe they seek the help of a god who is known for healing but has a difficult task for them in return.
Well, Percy could also try to expose the wrongdoings of those forcing him to marry. If there are any illegal or unethical reasons behind it, by bringing it to light, he might be able to get out of the forced marriage.
Percy could use his wits. For example, he could outsmart Luke by using his knowledge of the fanfiction world's rules or magic. He could also find allies. Maybe there are other characters who dislike Luke's bullying ways and would be willing to help Percy.
Percy could start to form new relationships within the Faunus community. These relationships could teach him different values and ways of life. Maybe he'd meet a Faunus mentor who would help him understand and control his new Faunus powers, if he has them. This would be a big part of his development, as he'd be learning from a completely different perspective than he's used to at Camp Half - Blood.
Well, in some fanfictions, Percy might go on a dark and brooding path. He could isolate himself from his friends at Camp Half - Blood, feeling like he's alone in the world now that his mother is gone. He might throw himself into more dangerous quests, almost with a sense of self - destruction, believing that he has nothing left to lose.