There are professionals that are now treating and classifying computer games as an addiction. A mental health professional can identify the limits that need to be put on this addiction and how to resolve this with appropriate consequences. A child therapist can help you put in place measures to reduce participation. Possibly a rewards system. Find out before you make an appointment if the clinican is well versed in addictions in teens. The family can then work to set firm limits. You can also work with the school counselor to identify rewards or negative consequences for his addiction. Her being in the school can address this problem on days when he is "tired".