He wants to read to his class now, but his teacher has (IMO, wisely) tried to diplomatically steer him away from that. (They all know he's different, but no need to overemphasize it by having him play teacher, I think.)
My DD's pre-K teacher turned story time over to DD, and the class treated her like a rock star for it. DW volunteered to chaperone a class trip, and all the little ones were so eager to tell DW how smart our DD was... in case DW was unaware, or something. It was adorable.
And as a differentiated instructional method, it was excellent, because DD was working on a different skill set that she was developmentally ready for, while the kids were working on another one, listening along.
YMMV, depending on the personalities involved. The teacher's attitude here is an important one. If your DS's teacher is hesitant, that'll probably influence the reaction of the kids. My DD's teacher was very supportive and positive about it.