Hi Joe! Welcome to Wrong Planet! Check out the interesting and helpful forums and articles here. Some of them are for parents of kids on the Autism/Asperger's spectrum. There is also a games forum, and kids forums, so you might like to check those out and see if they might be good for your step son to try out. Thanks for manning up to taking good care of your step son!
You are among friends here. 
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If a man does not keep pace with his companions, perhaps it is because he hears a different drummer.
Let him step to the music which he hears, however measured, or far away.--Henry David Thoreau