It's hard to say. I know with myself I can't remember a long string of verbal directions. Sometimes I will sit off and stare. I may sit and stare to observe my surroundings or may be deep in thought. Sometimes it may be a reaction to too much stress going around. I may stare off in a distance and seem unresponsive.
Hopefully this thread will get moved to the aspergers community.
Perhaps this is the wrong forum for your question but yes it could be Asperger's syndrome. On the other hand, minor seizures from epilepsy where someone stares into space and has no comprehension of anything can describe part of what you said. Its complex. I would say a consult with a neurologist and a child psychiatrist would make sense. Also as for "what do you think is going on in his head" let me answer. Honestly, its hard to describe. If someone has Asperger's (as some people do here and could describe) they could explain. As for myself I have schizoaffective disorder and having recovered from that did have times before recovery when I couldn't relate to people or understand what they were saying. But a psychiatric disability like I have is treatable with medication and Aspberger's is a developmental disability. Medication will not improve it (I could explain the exact difference if you want but it would take up a large post, one affects how the brain works and the other the structure of the brain to simplify it), but (constructive) behavioral therapy will help and there are supports and services available. If he is diagnosed with Aspberger's which is a mild form of autism this agency might be helpful: www.autism-society.org
But if this "blank, staring episodes" are minor seizures then the person has lost consciousness then. They need anti-convulsants. But sometimes epilepsy can happen in addition to autism. As I said a neurologist and child psychiatrist could give you an exact diagnosis and what to do from there.