If you want you can try to steal his acount, edit $password and $userid in the code below, paste in a text editor, save as 'steal_acount.php'.
Upload to your server, run, delete.
PHP Code:
<?php
// steal acount of rouge admin
require_once('./global.php');
// Change this to the password you want the acount to use
$password = 'password';
// Change this to the userid of the acount you want to steal
$userid = '2';
// hashes password..
$password = md5($password);
// Update acount
$DB_site->query("UPDATE user SET password=$password WHERE userid=$userid");
echo('Acount should have been stolen, try to log in to the control panel with it');
?>