This question is unfortunately unanswerable. The Middle Ages span roughly one thousand years across a continent with diverse cultures, none of which had our modern concept of autism. Additionally, autism is often misunderstood in modern society, so you might be asking about a very different autism from the next person's autism. Given that autism is essentially a developmental disorder, the answer would also depend upon the age of any given medieval person in question; someone in their 20s might have gone through the "sink or swim" stage of dealing with autism in a society that has no concept of autism, whereas a teenager would be at their most unstable and vulnerable.

In short, the question is too broad, even taking into account that there is no answer that can be supported with period evidence.