Now the B.S. begins

I am sad to hear this. Perhaps there is a legal aid service near you that can take the case pro-bono and help you get through this.

The current holder of the vehicle cannot title it without your signature based on what you have said...and that is leverage. Based on it being part owned by you and your step daughter, they are stuck unless you sign it over.

The buyer can file a mechanics lien but he cannot title it without a signature.

He’s just as screwed as you are...and that makes for a level playing field.