re: What do you do when grounding doesn't work?

You have to find his pinch point and apply pressure. You know him and we don't. I would guess his phone and any other connection to the internet would be one. If he needs the internet for school then a laptop/desktop in a family common area would be his only choice if it were me.

I understand your reluctance about homecoming but would you not fire an employee that stole and broke stuff just because they have a family?