That sounds more like an Android lock screen. Since he must have hacked his iPod Touch to get it on there, there isn't much we can do. You'll have to reset it. If he was smart and backed it up regularly, this shouldn't be any problem.
As the other poster stated, the lock screen is there for a reason.
You won't be able to get in without knowing the combo.
You'll need to hook it up to itunes, and restore it from a backup, or doing a fresh install.
Both of these options can be one by clicking on the restore button.