Look online for the USCIS office nearest you. Each USCIS office has a fraud detection section. Send your information there.
The answer provided here is general in nature and does not take into account other factors that may need to be reviewed for a more precise answer. You should consult with an immigration attorney before taking any action. The answer here is not intended to create an attorney-client relationship.
That is just a terrible thing for a parent to do. I agree with my colleague to report it to your nearest ICE office or call the ICE hotline. There will be others like you willing to testify to this matter.