I don't know of any laws he broke-- he is in a 13 (which protects co-signers) and he is paying the home-- he had to include any and all debts-- the only issue I can see here is a civil issue-- between you and him-- see if he can refinance the home to get your name off (I doubt he will be able to per he is under a 13) what are your plans with regard to the house? Him keep it, you keep it or sale it?
Who ever told you he violated a law, I would contact them and ask them what law he violated as I have never heard of anything like that --however in the 341 meeting the trustee must have asked him about you-- if so, and he lied, then he committed perjury, Maybe contact the bankruptcy trustee's office and talk to them about all of this.