What strikes me as authentic in this film (and to some degree in most Pixar films) is the boy-like wonder and innocence in their view of the world. Kids, in general, whether they are born in harsh circumstances or not, they maintain (for a handful of years that is) their wonder, their unadulterated (pun intented) approach of discovering the world and who they are.
So, to get back to your question, the boy is not really that special, in my opinion. It's just a boy. Most likely other movies have lost touch with the relentlessly awe-inspiring experience of being a kid.