Help protect my son from an abusive illegal alien

I am a desperate mother of a 4 year old trying to protect my 4 year old from an illegal alien. He has 2 DUI for drugs (heroin), numerous arrests for theft, buying heroin from an undercover police officer, and drinking as a minor. He has NO papers but obtained a social security number that comes back to his name for $10,000 as he admitted to me. He was abusive to me and nobody believes me. I brought in paperwork that he said he would sign over parental rights for $20,000 and the courts disregarded it. He pushed me off the road in his car into oncoming traffic and the police asked me if I took a picture. He smashed my windshield and the police suggested that since I could not place him at the scene that I say nothing and call my insurance company to cover the bill. PLEASE HELP GET HIM OUT.