No he will not, and if they try to contact the CDE and file a complaint. Thats what I had to do to even get my assessment done because they kept kicking my daughter out of class and I had to quit my job to be on call in case they called to have me pick her up (and she was only in class for 3 hours a day!)
The law protects kids with disabilities from punishment due to symptoms. No one should threaten expulsion. In fact, them planning an IEP meeting is a sign that they want to work with you and help your son, not the opposite.
Here’s some information on IEPs and the law for you to review to understand what is taking place better: