am I evil?

I'd call it showing tough love, not being evil. If his addiction is as bad as you say it is, he won't quit cold turkey. He'd have to find a hobby in real life to slowly take his mind out of the game until eventually the next time he logs on he finds it boring and decideds not to play. Doesn't have to be an athletic hobby if he's not built for it. Maybe he can learn to work with cars. Or learn to play an instrument. Again, you're not evil at all. It's called being a responsible older brother. If only other addicted Maplers' parents(or siblings) had the capacity to do what you did to their own kids. You're a hero IMO.