Don't think that there's a different, better child 'hiding' behind the autism. This is your child. Love the child in front of you. Encourage his strengths, celebrate his quirks, and improve his weaknesses, the way you would with any child. You may have to work harder on some of this, but that's the goal.
My son, who's on the spectrum is a very rigid thinker. He needs clear-cut definitions of right and wrong. Anything hazy or gray confuses him. For instance, if I try to get him to see that a friend behaved badly, he'll often get upset with me because a friend is a 'good guy' by definition, in his book.