Called police on brother cops won't respond?

My brother has been arrested like 16 times mostly ALL for violent attacks. He's 24super alcoholic and on steroids and he's a scary beast of a man he went to prison for 3 years. One of his child's moms kicked him out tonight and he came to my parents house and my dad said something he didnt like and he choked my dad and threw him through the glass screen door. He also punched several holes in the wall cut himself with glass on his arm and ripped the toilet off the hinges. I called the police and they said they would make a report but wouldnt come out because we've called so many times before and my parents failed to press charges and my brother stabbed a officer one time and got off cause he's clinically insane because he was in the marines in afghanistan. I'm really scared cause I know he has a gun and a knife on him and sitting on the patio growling like a dog what do I do the operator said too big risk for the officers if my family wasent serious about pressing charges?