Use the service at
Read More
to report her.
The longer she stays the more of an issue it will become for your DH. The more of an issue it becomes for her then the more it will affect your employer/employee relationship. It is obviously affecting it already otherwise you would not be posting this question here.
If you value your DH do her a favour and hand her sister in. If you don't worry about losing your DH then let it continue to run.