A child or student with ADHD can be excluded from school without a meeting for a period of 10 days.
The child or student with ADHD would have to do something serious enough to get a suspension from school and then get expelled.
A school would have to prove that the child with ADHD cannot be controlled in the school by the teachers and is causing a problem.
But the school cannot expel or exclude a student with ADHD just because they have ADHD such as a public cannot just tell the parents that they won't accept the ADHD student when you enroll them.
If they do exclude the student for ADHD without a meeting then the school will be putting at risk their LEAs and SEAs for litigation and lawsuits.
The school can be sued and have a lawsuit against them because of their failure to provide an appropriate public education to the student with ADHD.