My twin brother, Jack, has cerebral palsy, hydrocephalus and epilepsy, and although I hardly ever came across disabled characters in fiction I never came across witches and wizards in real life, either.
Jack can't read, but he loves having stories read to him. How much he fully understands these stories I don't know, but he likes the rhythm of the words and he can tell when something is rude or funny.
Jack doesn't have the understanding or concern about not seeing himself represented in fiction, but I am and I know many other families, siblings and disabled people themselves would hugely benefit from seeing stories of people like Jack in their day to day reading.
Growing up, whenever I picked up books which centred around disability, the ending was always tragic. One of the saddest books I've ever read, Red Sky in the Morning by Elizabeth Laird, ended with the death of the main character's little brother, who had hydrocephalus. I read another book in my school library about a boy whose best friend had muscular dystrophy, which ended with the best friend's death.
I have nothing against these books; they were both plausible, and probably written as a way of helping children cope with loss, but I didn't understand why disabled characters couldn't have happy endings. I wanted to see them able to have adventures like everyone else, where their disabilities were not the main part of the story.
The problem is lots of children's books are about characters with magical powers, with children who have enhanced abilities rather than disabilities. The Percy Jackson series by Rick Riordan did the most to change this, with all the teenage demigods having ADHD and dyslexia as a side effect of their godly powers. However that didn't extend to characters with physical disabilities.
I remember being surprised reading a book called Scribbleboy, by Philip Ridley, when the main character made a new friend who used a wheelchair. I still remember the scene where he was introduced. He comes through the door, and at first the main character thinks he is very short before realising he's sitting down. His disability is never really mentioned again, although he's in the wheelchair throughout in both the story and the pictures. This was perfect. It wasn't necessarily what I needed, because I wanted positive stories about disabled siblings, but it's how I'd want to be represented in fiction if I used a wheelchair.
Another great book series, by Hilary McKay, had the children in the story walking past a girl in a wheelchair and never speaking to her because they felt sorry for her, which in turn made them uncomfortable. I read it when I was about twelve, and it reminded me of people (other children, particularly) staring at Jack in shops. I knew these people weren't mean and didn't hate disabled people, they just weren't sure how to react. Although I wouldn't have wanted to admit it, I used to feel the same about disabled people who I didn't know. I think it's important to show those feelings in books, to address negative attitudes without having to go for full-on bullying or tragic death.
Those books also resolved the story in the best possible way, by having the main character get to know the girl and become her friend. After that, her wheelchair just became a side note about her, like having dark hair.
I don't want to read books that treat disability as a tragedy, putting the stories in the same category as books about child abuse or people dying from cancer. Books where the disabled character dies aren't terrible, but they can't be the only type out there. I never wanted to read the absolute worst-case scenario portrayal of having a disabled brother. My brother and I were both happy.
I would have liked to read more books where a character's disabilities were not treated as an issue, just one part of their character. More vitally for me growing up, however, I would have loved a story which showed having a disabled sibling the way I saw it; not as something sad or embarrassing, but just a normal part of life.