He's not "withdrawn" ... he's NOT INTERESTED! there's a huge difference!
Not having met your DS, I can't speak to that specific situation, but in general, there isn't always a huge difference.
A person with autism tends to be drawn intensely to their own, often limited, topics of interest. Until they learn how, many are not capable of getting interested in something simply because someone else is interested.
Most typical kids will easily get interested in things if another person demonstrates an interest-- that social pull can drive the intellectual engagement. For an autistic person, the lack of interest can be in part due to a lack of social perspective-taking-- not being able to appreciate what the other person finds interesting.
DeeDee
