Can you seek legal help to protect yourself from an obsessive ex?

My best friend has been dating a guy on & off for almost two years now. He not only makes her life miserable but her friends family & any guy she tries to date as well. Shes tried numerous times to get away from him but he will not leave her alone. He threatens her blackmails her & slanders her name to others. Hes physically aulted her & her personal belongings(clothes car & cell phone). Anytime she tries to date some one else he finds out who it is & makes sure that he ruins whatever potential relationship she might have with someone else. Hes made fb pages slandering her name with naked pictures of her on the site & sent naked pictures of her to numerous people via text. He's even gone as far as saying his mother died to try to keep her around & kept that lie going for months by saying he was going to her grave & whatnot. He's threatened to kill himself & has sent pictures to us with a gun in his mouth saying that its our fault. He constantly text her mom saying that hes going to kill her & her family "or her crippled husband". Her dad recently had a heart attack & he doesn't need the added stress of worrying about his little girls safety. He's even threatened me saying that he's going to blow my head off if I don't tell him where she is. Shes scared of seeking legal help & says that he'd only end up getting out of it & make things worse for her. She's called the cops numerous times though so there's doented proof of his craziness.Shes heard that a restraining order in Maryland only lasts 6 months & she's worried that it will only piss him off more & after the six months he'll come after her even worse. I want to get some info for her of things she can do to protect her self & her family against him. My biggest fear is that Im going to get a phone call one day saying shes badly hurt in the hospital or worse. Please help!