This Side of the Fence - Pupils With Autism See It Differently
Reading your story, the thing that strikes me most is the problem you have presenting concepts step-by-step. "Allists" seem to have some fuzzy state that constantly holds a somewhat accurate image of the current situation. (Don't ask me how you do that.)
Without that, we need solid reference points to start from, and these can be a long list of assumptions away from what you're asking of us. So, if you find your pupil is taking long to process a simple instruction, could you ask yourself what makes it simple for you, and what stepping stone he'll need to make it simple for him too?
Likewise, the alternative ways to play something: It sounds like you forgot to teach him that there can be more than one way to play a piece of music. And did you actually explain rhythm, or are you just asking him to play set lengths of notes?
Let me invite you over to this side of the fence for a minute:
Imagine that everything around you is loud. You're not just wearing glasses that enlarge all movement and hearing-apparatus that makes all sound louder, but you constantly have sensations from all your senses, whether it's the keys feeling warm or cold, the way this piano smells, the uncomfortable seat, or even how the relative position of your hands and elbows makes your wrists bend and makes it unnatural to stretch your fingers.
Now keep this loudness in mind, and listen to your own conversation during the day. How long can you go before you're saying something that is either unfounded, contradicting something you've said before (or someone else said), a (white) lie, or an implicit message? When you say these things, you create impossibilities. Now, how would you, in our loud world, cope with someone who says something impossible? And now if you can believe it, accept that likely no-one will ever tell us how to vent that reaction; they'll only tell us not to ... yell, ignore them, stick out our tongue, hit the piano ..., but not what to do instead, let alone what it is that is frustrating us, and not at all that they themselves are causing these situations, simply because they don't know any better.
OK, you can go back to your side now.
There are many different symptoms for this spectrum of diagnoses, but so far this is true for anyone of us that I know: We experience every sensation more intense, and we don't have the fuzzy current situation state. So, if you add to the information, we have to connect it with what we know, but at the same time everything around is usually calling for attention.
Help us by making the steps we need to make smaller, by introducing the facts we need first so we can build on them. And don't give alternatives to a fact. (I first wrote "absolute truth", as that's the allist way of saying. But to an autist, how could a fact be less true than absolute?)
Rather than contradictions to a fact, you explain the concept of alternatives first. Then, preferably after we've had time to sleep on it, your introducing alternatives will be an addition of new facts, rather than a contradiction to the existing ones.
Film music will often have several versions of the same tune. Different instruments have different versions of the same score. Different sets of lyrics often bring slight changes to the tune. There are several ways to demonstrate that there's more than one way to play the same piece. Once you've successfully introduced that, you can introduce versions to music you already presented as fact. Of course, you should simply be honest up front and make clear that you are going to add a different way of playing later ...
Other than that, check (with parents if necessary) if your pupil reacts sensitive to the (full and new) moon, so you can anticipate, and ignore anyone's explanations about the cause of autism until science has brought the number of explanations down to one.
I agreed to the submission guidelines, but of course my nature makes it necessary for me to comment that I see no reason why the website guys should be allowed to keep anyone else from putting my words to good use.)
I appreciate your insight and your perspective on breaking things down into many small steps. That has always been something I have struggled with as a teacher - I'm sure many of us take a shared perspective for granted.
In line with that, I have made some tiny edits to your letter, because you, too, are making some assumptions... I have never heard the term "allist" before, and I want your letter to communicate your message as clearly as it can.
I'm thinking it may be a long time before science makes its final pronouncements on autism. Until then, parents and families will continue to seek to know all they can.