While this may be one of the worst moments of your and your child’s life, it’s just another day at the office for most medium sized universities. Every semester they will get a list of students that will be dismissed and they’ll go through the due process motions to dismiss them. They normally have a route to re-admission.
Being a helicopter parent may do you more harm then good. Just tell the kid to be respectful, apologize and promise he’s going to work on his issues and try to do better. There’s not a lot more to it then that for an academic dismissal, (as opposed to a misconduct dismissal.)