I don't have any info about what to expect, but DS9 has been in classes with children with various diagnoses and disabilities and had frequent interactions with children I worked with in a SpEd classroom. The teachers provided guidance in the classrooms, when necessary. If I happened to be around, I found that DS watched me and my actions and just kinda took it from there. If he seemed uncertain about or didn't understand something, he'd follow the lead of an adult and then we'd talk about it later. He handles himself very well around those with special needs and doesn't seem uncomfortable at all. Sometimes, he does have questions, but he's learned to wait until the appropriate time/place to ask.
Perhaps if you're planning a playdate, you could be there to get to know the child/ren and also be available to help your child with anything he may not understand.
