Howler's daughter has used a method she calls the Jane Goodall approach. Maybe you can have your son research her and then see that he can pretend to be Jane Goodall but instead of studying chimpanzees he is scientifically studying humans whenever he has an assignment like that. Maybe see could explain it more.
I feel for you....my son has ASD and occasionally has problems with assignments that mess with his rigid thinking (but only two last year....so we are down from weekly in 4th grade to two of total in 9th grade.)
