How do I keep my son from his mother who is drinking heavily and unfit?

She moved to Madison WI. I live in Fond du lac WI. Recently on 11/11/18 Mindy called me at 8pm told me to get our son she did not want him there to live anymore. she was drinking. Police were involved and they told me that Mindy did state she did not want him their and my son told them he wanted to stay with me. I have not received the police report yet but she and her husband also threatened me and my girlfriend. She contacted me on 11/13/18 and said she was picking our son up on 11/16/18 and taking him home with her but for his safety, I do not want to. How do I do this without getting in trouble for keeping him and going against court order? I do not want to send my son where I know he will be harmed.