Where Do They Fit?
There really is no place, in the services provided for disabled people, for a person who has severe developmental disabilities and is highly intelligent and able to communicate. As far as many service providers are concerned, these people don't exist.
In some ways, these people face similar issues to people with severe physical disabilities (such as quadriplegic cerebral palsy) and no other disabilities. Both groups are of average intelligence and can communicate their wishes, but need significant assistance with activities of daily living. And both groups are likely to be assistive communication users.
But autistic assistive communication users don't fit the mould for physically disabled people either. Firstly, though their cognitive abilities may be better than previously thought, they still have cognitive differences, often very pronounced cognitive differences (eg Carly appears to be a visuospatial thinker). These differences may somewhat account for their severe difficulties (though motor apraxia seems to be the biggest issue) and certainly impact on how to present information so they can readily understand it. In some ways, they'd be more like a physically disabled person who also has severe dyslexia or another specific learning disability.
Another issue is behavior. Physically disabled people are probably not significantly more likely to have 'behavior problems' than nondisabled people. When they do have behavior problems, their physical disabilities may make these issues less problematic - a physically aggressive person with very poor arm strength and no leg use is less able to actually cause any harm than an aggressive person with no physical disabilities. In contrast, many nonverbal autistics who use assistive communication have the same kind of behavior issues that are commonly associated with autism, such as self-injury, aggression, screaming or running out in front of cars. These behaviors don't deserve nearly the stigma they carry, but they are still issues that can complicate services for these people.
And not only may their behavior pose a problem, but their sensitivities as well. Most nonverbal autistic people seem to have marked sensory processing issues - to a greater degree than high functioning autistics like myself. I noticed this with the one boy I worked with who seemed like me but more severely autistic. The same things that caused me mild discomfort would make him completely fall apart. I've heard some people with severe sensory issues describe feelings of overload that are as foreign to me as I suspect my overload is to neurotypicals. (I do think that anyone, if pushed far enough, can experience any degree of overload. For example, some of the coping strategies used to deal with overload are also used by severely traumatized people. But most people have never been pushed as far as some everyday events can push a person with sensory issues.) Sensory issues are one of the few disabilities that can genuinely make someone unable to be integrated into a mainstream class - if the person is in perpetual overload whenever there are more than 5 other people in the room, for example, they won't be able to handle a classroom of 30 kids.
(I just thought of a good analogy for the differences between my sensory overload and the overload felt by some nonverbal autistics - it's like the difference between asthma attacks that cause mild chest pain and difficulty catching your breath and asthma attacks that put you in the emergency room.)
Another issue is inconsistency. Partly this is due to sensory overload, partly due to motor apraxia, and partly it seems to just be a natural learning style, but many nonverbal autistics are very inconsistent in their abilities. They may be able to do one thing but not a seemingly-identical activity, or do something one time but not another time. Even their assistive communication use may be inconsistant, meaning that even though you know they can type, they may not be able to type right now. Carly, for example, in her early years of typing, would unexpectedly stop typing for a couple weeks at a time, and then start again. She later explained that she was simply taking a break because typing was difficult for her, but at the time her father found it quite confusing.
There needs to be research done into the needs of people with severe developmental disabilities such as autism and high level assistive communication abilities. How do you best educate someone who is at a normal grade level academically but types to communicate and unexpectedly starts screaming and self-injuring? How do you manage times when they are temporarily unable to communicate, either due to skill inconsistency or because their communication device is broken or not present? (For example, if the device isn't waterproof and they're going swimming, or if the device got lost or stolen.) What kinds of learning styles do these people often have, and how do you teach to the way they learn best? How do you create an environment that is safe for a person who finds ordinary sensory stimulation excruciatingly painful?
Furthermore, it's likely these individuals are the tip of the iceberg. How many more individuals have just as much potential, but haven't found a communication system that works for them? More research needs to be done on ways to help these people find their voices. But when they do, will we be ready for them? Imagine if it turned out that 50% of people with severe developmental disabilities could communicate at a high level with the right support. How would this revolutionize the service provisions? (One specific way, sadly, is in casting light on crimes done to disabled people who are assumed to be unable to ever report on them. Many assistive communication users have alleged abuse at the hands of care providers. These people may end up doing a huge favour for those who never can communicate enough to report abuse.)