Obviously, Amy is an important character as she is the one who gets sick. There might also be her best friend, who could play a crucial role in taking care of her and being by her side throughout her illness.
In this fanfic, apart from Amy, there could be a love interest. This person might be deeply affected by Amy's sickness and could be torn between their own life and being there for her. Maybe there's also a mentor - like figure who has some wisdom to offer regarding Amy's situation. They could guide the other characters on how to deal with her sickness, whether it's through practical advice on finding a cure or emotional support.
The important characters could include Amy's family members. Her parents might be worried sick and trying every possible way to make her better. Her siblings, if she has any, could also be involved, either being helpful or causing some sort of family drama because of the stress of Amy's illness. And then there are the friends from her school or community in the 'A Secret Life' world. They might form a support group for Amy, each bringing their own unique personalities and skills to help her during this tough time.
In this fanfic, perhaps Amy's sickness could lead to her friends rallying around her. They might show different sides of their characters as they try to take care of her.
Lou Fleming could also play a major role. As Amy's sister, she could be the one taking charge of the household while Amy is sick, making sure everything runs smoothly.
Perhaps in the fanfic, Amy Fleming's sickness is a mystery. The story could focus on her trying to figure out what's wrong with her while also dealing with her daily life on the farm. She might have to rely on her horse for comfort during her illness.
Definitely Ty Borden. He and Amy have a special relationship, so he would be deeply concerned about her illness. He could be the one running errands, getting medicine and making sure she has everything she needs. Georgie could also be a main character. She could be helping Lou with the ranch work and also spending time with Amy, telling her stories to keep her spirits up. And then there's Spartan, Amy's horse. Spartan could be acting strangely because he senses something is wrong with Amy, and his behavior could be a part of the story as well.
In the fanfic, Amy's sickness could also lead to some comical misunderstandings. For instance, Sheldon might misunderstand her symptoms and think she has a very rare and dangerous disease. So he starts panicking and over - preparing, like building a quarantine area in their apartment. This could lead to a lot of funny moments as the other characters try to calm him down and deal with the real situation of Amy just having a common cold.
Her best friend could be a main character. This friend might be constantly by her side, bringing her schoolwork so she doesn't fall behind and also sharing the latest gossip from school or the stables.
Maybe there could be a neighbor who stops by. This neighbor could be an elderly person who has some old - fashioned remedies and shares stories with Amy while she's sick at home.
The neighbors could also play an important role. They might be the ones who notice something is wrong first and inform Amy. Later, they could bring over home - made soups or offer to babysit other children if Amy has more than one, so she can focus on the sick child.
His friends are very important. Rukia, for sure. She has a lot of knowledge about the spiritual world and could be the one to figure out what's wrong with Ichigo. Orihime with her healing powers also plays a big role. She might use her abilities to ease his pain or at least keep his condition from getting worse. Uryu could also be important as he might use his Quincy skills to analyze what's causing Ichigo's sickness.
If it's in a work - related setting, his boss or colleagues could be significant characters. His boss might be understanding and give him time off to recover, or his colleagues could be worried about how his absence will affect the work, which could create some interesting plot points.