You can get a family court protective order. However if she continues in this behavior you'll have to decide if you really want to turn her over to the police. A 911 call for violation of a protective order will land her squarely in jail. You may prefer to check out community programs desiged to help her deal with her issues.
Depending on all the facts of your case (including the nature of the threats), you and your family may have a variety of options, including, but not limited to, reporting the criminal activities and obtaining a protective order or a peace order. The mere existence of a familial relationship or mental illness does not give her immunity from telephone harassment statutes or a license to make 20 phone calls targeting your minor children. I recommend meeting with an attorney, in-person, and calling the police to the extent you believe you (or your children) are in danger.