I need to compromise the password on my child's phone as well, I want to read text messages without his knowledge that I am doing so. Does the owner have an override capability on all the devices he owns to bypass passwords?
Just take his phone away for good. If he doesn't want you do be a parent then treat him like a 4 year old. Buy him a pager, and if he doesn't respond or show some responsibility then take that away and lock him in his room.