Hi Charlie.
My daughter has this as well. When we went to our family dr I shared that I thought she had misophonia and the dr actually knew what it was! Had her write a note for the school to put on file that she can wear headphones, etc. if she needs. Only paid a regular copay. No school can discriminate against people who are hard of hearing and this should be treated similarly. It is considered a disability. Hope you can find a dr who will diagnose this for her.