I'm going to guess that this is very simple; he probably just has the option for requiring a password at login turned off, or is using Fast User Switching enabl

I'm going to guess that this is very simple; he probably just has the option for requiring a password at login turned off, or is using Fast User Switching enabled (i.e., the user is question was not really logged out, so logging in and entering a password is not required), or something like this.