None of this is your fault or your parents.
None of you have done anything to be ashamed of.
Don't compound your father's unfortunate mistake by cutting the woman slack because 'she doesn't have anything'.
I don't think you should be the one going to her employer either. That's an attorney or law enforcement officer's job.
Contact your state's elder abuse authority. You can find it at
the NCEA site. They'll be able to help you decide if you need an attorney and will likely have recommendations for the best one to do the job too.
As emphasized above, don't wait! Do this today.
Good luck to all of you.