Question: What happens if a school requires masks but a student with a disability cannot wear one?
Answer: A student with a disability may be entitled to an exemption or modification to a face covering requirement as an accommodation under the Americans with Disabilities Act (ADA). This would be determined on a case-by-case basis.
Here is some information from the Southeast ADA Center on face mask requirements and ADA accommodations. This piece isn’t geared towards schools but it provides insight into the considerations.