God bless your sister.
Blooming Idiot berg would have told her that she doesn’t need a gun or a knife. Why - simply get a restraining order against the man, and if he shows up, why call the police.
Thanks. Quite honestly, the man terrorized her away from the family for many years. She has been diagnosed with PTSD. After only hearing some of the stories, I can see why. If I ever see him or hear about anything he does, it will not end well for him.