The best thing that you could do in this situation actually isn't trying to take him off the video games. The best thing to do is try to shift his isolated video game playing into a social environment.
Are there any lan places around you that might run tournaments for the games he plays? Tournaments at such places allows a player to meet other players and becomes friends. It may not cut down his playing much but it will make him more social and the fact that he would need money to go to all the tournaments would encourage him to go to work more. If he is good enough he can also make money off the tournaments too.
Amazingly video games can be a very social experience in this nature. The bonds I have made meeting people through video games are greater than friends I have made in sports and school, and are comparable only to my church friends.