Since your son is 16 years old, he is what we call an 800 pound gorilla. Do you know the old adage, where does an 800 pound gorilla sleep? Anywhere he wants. So, practically speaking, if your ex is using drugs and your 16 year old doesn't want to go over there any more, he will not be forced to do so, either by the court system or local law enforcement.

The child support is another thing. If you have an order to pay chile support , it is due until paid in full and there is no statute of limitations on collecting the past due money. However, you can discharge your child support by having the child 100% of the time under a case named Marriage of Jackson. This does not help you if you pay support by way of a wage assignment. The only way to get the wage assignment stopped is by going to court. Also, if you want support from your ex, you must go to court for that order.

The long answer is you do not necessarily have to go back to court to obtain custody of your 16 year old child. The short answer is if you want to avoid any potential future problems, keep your son with you, do not send him back to Mom's, and them play it safe and get a court order modifying custody and support.