Dear *****, without understanding what the underlying causes of Jon's symptoms are it is difficult to assess a plan of action but I can make two recommendations;
1). that you continue what would be considered tough love, making sure that he understands that you are doing this out of concern for him and will no longer participate in his unhealthy decision making, and give him as many positive and/or negative consequences for his decision making as possible. (Btw, it is always more effective to use the positives if possible) so for example agreeing to turn the internet back on for the day if he agrees to a one hour conversation with you to discuss what is happening to him. And also consequentially, taking away something else he wants as another negative result of his behavior. This is the time for you and his mother to work together creatively in problem solving how to reach your son with the goal of getting through to him in a safe, caring way to understand that he needs to get professional help. The goal here would be to make this as difficult as possible for him to continue this passive aggressive way he is communicating his anger/pain.
The reason I asked about whether he has siblings is that including a person he cares about or is close to, to help reason with him may be helpful as well, instead of this being a contest of wills between him and his parents.
2). If he continues to be uncooperative, it would be advisable for you and your wife to seek a psychologist who specializes in family therapy to direct and counsel you both on how to learn behaviors that will not enable his choices and decisions. Right now he feels he is in control, but is also expressing pain underneath this pain/anger. As you can see you can not ultimately control how another person behaves, it is up to him to decide to handle this situation differently, but a clinical person will help you both evaluate what your part is in the dynamic and help you to learn those new strategies that you are needing.
This is a very complex situation that did not happen overnight. You stated you made a move on behalf of your son so that he can play music..........that is a great deal of commitment to him and control on his part for the family decisions. the three of you may have developed unhealthy patterns and roles with each other that a professional will be able to help you with identifying and changing. Ideally it would be best for all of you to eventually be in counseling together. I hope these suggestions are helpful. Please let me know if you have any further questions related to what I have shared here. sincerely, ***** ***** LMSW, CASAC