I hope his lack of roles beyond 9-1-1 is his own choice...
And not based on his disability... This kid is likable in every way, and displays some real talent in conveying emotion in his character on the show. I think that, should he want it, Hollywood should be hitting this kid up to star in his own show/movie. I can tell that he has a lot to say about life, both as an actor, and as a person with a disability. You can really pick up a lot of emotion in his acting role on 9-1-1 that shows a depth of emotional understanding that could serve him very well in Hollywood.
Make it happen, Hollywood!