My mom was arrested for stating the wrong date on a police accident report what are possible consequences

Your Mother needs to retain a lawyer as soon as possible. If she is detained without bail, she would be entitled to have bail set. If you cannot afford counsel right away, you need to find out from the court clerk the name and phone number for the lawyer assigned to represent your mother. You need to contact that lawyer and find out as much as you can about the case. What the cops said about your mother's case might not be true at all. There probably is a felony complaint filed against your mother alleging that she committed a specific crime. It sounds like your mother is being charged with some kind of insurance fraud or offering a false instrument for filing, but a competent lawyer would need to review the documents. Good luck.