Legal Question in Family Law in Missouri

Probably not. The police won't make him come home, and you probably can't. Until the court order is changed, the obligation to pay child support continues, but I'd stash it in an account pending a resolution of this mess.

At 18, he's a legal adult with the absolute right to run turn his life into a train wreck. A parent is obligated to make decisions for their minor children according to what the parent, in his or her adult judgment, believes to be the child's best interest. However, your son is no longer a child, he himself is now a person with adult judgment, and you are no longer required to decide what is best for him. He is legally able to decide if he will smoke, if he will attend school or not, and where he will sleep at night. But you are entitled to decide when the doors in your home will be locked at night; (you don't want an intrudor entering, do you?) and whether or not you allow smoking in your home.