I think this is a legal situation where the police and/or other authorities need to be involved. If she has been/is being abused, she can report him, get a restraining order, police protection...whatever is necessary.
He could destroy her family and /or career....in what way? A career is nothing without a life...If there is evidence, bring it to the police, or maybe they would start keeping an eye on him to get evidence of their own. There are always options...but I think going at it the way you are is not going to solve the problem.
I guess it comes down to how she wants to spend the rest of her life...if she isn't willing to stand up to him, then she has to consider how long she is willing to live the way she is now....tough decisions....good luck!