Got a Kindle Fire for the kid for Christmas, great with games, photos, videos and music.

Parental Controls are on, but he's clicked his way to de-registering the Kindle Fire, and in doing so wipes out everything, and he's also managed to change to language to German. So we reset everything, but cannot find anyplace to stop
him from deregistering the kindle or from changing the language preference.

Help would be appreciated.