Sometimes a therapist and a client do not mesh and the client is not seeing positive results. This is more common than we like to admit. You seek certain qualities in a therapist knowingly or unknowingly. When you are not compatible you can see a process that really is not getting anywhere. The other possibility is that he is suffering from a mood disorder and he is struggling to find the energy to make the changes suggested to him. I may consider going to another therapist that is a good fit for him. Or finding a mentor that can model for him healthy coping skills. Even though he is 16 there are agencies in any state including Big Brothers that help him connect with someone. Think outside the box and try creatively to offer him additional support. He may respond well to a male who has mentoring skills even if someone in your community,church etc.
Please press positive feedback so I am compensated