She *could* try locking him out of at least using the internet using a software/hardware (router) combination. She should start by limiting the internet times using off the shelf router solutions. My guess is, that might not be in the wheelhouse of the aforementioned 'addict'.
If that doesn't work, she may have to spend a little more to involve someone with custom programming skills to keep her son from changing the router settings. Most of the time though, I find pc or internet saavy kids not fluent enough to get around such custom measures. YMMV.