If someone is addicted to virtual world, are the roots of the addiction lie in the virtual world? Or maybe its a problem of the real one, which seems to be too much uncomfortable for a young man? He's 20 years old and he's bearded. He is not interested in life. VW is a problem! That's easy to say. He likes heroine - the problem is heroine! He likes MJ - the problem is MJ! Let's jail all those programmers, designers and artists with all the drug-dealers to one cell. Is that the way out?
How many active healthy people have you seen, who play virtual games all the day? How many successful people have you seen, who take heroine? Is that because they're so smart for not to try? Or maybe that's because they're just not interested? Why there not interested in such activities?
How to deal with it? Do you really think that you may stop someone from doing something by reading books? I would say for myself. I was the guy like him. I was out of university twice because of games. There was nothing, absolutely nothing as interesting for me as computer games. But time heals. He would be healed by himself. Or die playing. That's life - and that's his choice.
P.S. Or just kick him off the house to make him build life of his own.