From whatever is known about autism, it is an accepted fact that autistic children do not tell lies. They do not have the social skills to see how something would sound and to then distort what they know. Since you have read widely about autism, you have probably come across many books. One such book , which is also the winner of the Whitbread Book of the Year, definitely worth a read is The curious incident of the dog in the night-time a Red Fox book by Mark Haddon. First published in 2003, I have read an edition published by Definitions in 2004. The story is told in the first person, in the voice of the autistic child and has a ring of authenticity, because of the authors understanding and empathy. Clearly, the boy in the story cannot lie. But autistic children are often very bright and may have a rich fantasy life.