James, a lot of your replies in this thread suggest that you view people with mental disabilities as lesser. The problem, as I see it, is much deeper than just people assuming that those with one disability have another kind of disability — the problem is also the assumption that people with mental disabilities do not have meaningful things to say and have less value than other people, or that being mentally disabled is a negative thing.
People with mental disabilities deserve to be listened to, as well. They deserve to be consulted on how they are portrayed and how they feel. They crave connection, and respect, and positive treatment, like any of us, and they are complex and have their own unique preferences and views. You can speak about someone you know well, as a friend, but you can’t assume that you know better than them about what is good for them just because your brain works differently.
And to be clear: our culture teaches people that intelligence is a major source of human value, and I myself have previously underestimated people with mental disabilities. It’s a really common viewpoint, and it’s embedded in how we all talk about “smarts” and “stupidity”. So I’m really not trying to dog pile or pillory you for this. But, I think that when we’re having conversations about respect for people with disabilities, and who has the right to pen a narrative, it is vitally important to remember that no disability is so “severe” that the person with it doesn’t deserve respect, autonomy, support, and empathy.