We went through a very similar issue with DS18. He missed over half the school year during his sophomore year due to illness and our state also does not recognize medical withdrawal for high school. I was only able to get any concessions after reaching out to the school board but we’re only partially sufficient. The only way you can get any control over the situation is to homeschool. I strongly recommend that you reach out to some of your local homeschool groups and see what your options are. You may be able to structure your school year in such a way that your son can heal. I wish I had. Everything did work out in the end. My DS has been accepted to 3 colleges with excellent scholarships. Keep fighting for your son. The school system truly does not care and you are his only advocate.