Eco, Landon Bryce's blog and John Elder Robison's writings (books and blog) have been useful for us in cultivating perspective about having ASD.

We started with Bryce's book "I love being my own autistic self" when DS was maybe 7 or so; it was startlingly powerful, even though very simple. Probably too young for your DS, but still a great tool for the younger set.

I am particularly fond of Robison's "Be Different," which DS also enjoyed, I think in 6th grade or so.