G.♣.
As the mom of someone on the Autism Spectrum, I would speak with my son's psychologist or his Occupational Therapist or possible his Speech Teacher.
When my son was in a traditional school, his classroom teacher sought advice from the special ed teachers. He now attends a different school, so his classroom teacher is a special ed teacher.
This is an area where you really might need to talk to an expert. It's likely not going to be as simple as another child (not on the spectrum) being afraid of a fly.