I use 2.0.0 client, so do my players, when he logs in he just stuck at entering brittain.. Any ideas?(Yes i did use search before posting this)

v2 clients are notorious for blackholing. They get stuck at entering britannia sometimes. The situation is worse with many items in the location and a laggy connection.

If you are in the game and can see that he has connected and online, then try summoning him to your location - hopefully one that doesn't have a lot of itemcount.