My son is 18 and informed me that he did not want his biological father at his graduation. When I informed my ex, he got mad at me and I told him that it was something he needed to take up with with my son. My ex then informed my son by text message, "If I don't get to see you graduate, we will box" and then informed my son's girlfriend by text, "I will give him some pads and give him what he deserves". I've already notified the police of the threats he has made. He has not been in my children's lives the majority of it because he was incarcerated and also because he chose not to and had nothing to do with his education and now wants to take part in my son's graduation. Does my son have to let him come to his graduation?