So you have not told your son that you do not want him using the medication to get you to come see him. If that is true, then just go visit him and tell him if you want me to visit just ask me. He is 16 and needs to know that it is okay to talk to you honestly. But if you really think it is a trick to just see you and he wants something else do not go. YOu have to talk to him. See what happens.