How to write an informal essay for a character interpretation?

I'm taking an English course from ILC and I have to write a character interpretation essay for Christopher Boone from the novel The Curious Incident of the Dog in the Night-time.

I want to interpret him as an archetypal hero by writing a hero's journey but I'm not sure how I can do this while interpreting his character.

Consider how the character starts off in the beginning:
brilliant, but autistic. Single-parent raised, mother gone. He seems slightly unsure of himself (not regarding intellect.)
He goes on a journey to find his mother, solve the dog's death, his father's "infidelity" with the neighbour.
In the end, the main character concludes that he solved the mystery and he "could do anything".
It's up to you how you analyze it. What archetypal heroes go though - trial that changed the life of the hero (perhaps the dog's murder? or mother leaving?); realization of self (he is special? etc.) and so on.

thanks for the help. :)

Sounds like a great theme.. but which archetype is he? Google this: heroes archetypes list

Next, skim through the story and find examples to support your argument that he is this particular type of archetype.

:-)