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.
When our son's autism was diagnosed at the age of 2, there was no clear prognosis. We didn't even know if he'd ever learn to talk. But we found talented people to work with him and he improved, slowly at first and then more rapidly.
Sometimes people say that kids with autism aren't capable of love. That's ridiculous. My son loves deeply. He just doesn't communicate well.
Once your kid reaches middle school, parents are really supposed to fade out of the social picture. Kids are supposed to make their own plans, keep up with sophisticatedly crude discussions, and be able to go out on their own without supervision.
For a long time our son was a little boy with autism, which was a certain kind of challenge. Now that he's a teenager with autism - and a teenager who notices girls - we're faced with something else altogether.
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.