If you'd like him to log in as his own character, access the log in menu from the main menu and have him log in. Alternatively, he can use the /login command from a server.
/login username password
If you'd simply like to log out, go to your Toribash folder (on Windows operating systems, that'd be C
![Rolleyes](https://cache.toribash.com/forum/images/smileys2/rolleyes.gif)
Games\Toribash-3.x) and delete tblogin.dat.