I know i always say this, but this time i really mean it - get a gun. I know, violence doesnt help matters, but if this guy poses so much risk, it's the only way you can be safe. You'll have the upper hand. I dont suggest shooting, but if he does come round and start any trouble, a gun is the best way to protect you and your family. He sounds like a nasty peice of shit imho, and if he does want revenge a restraining order wont do shit. At least with a gun you can control the situation, and if you have to, shoot for the arms and legs. At least then he cant away and he cant harm anyone.
I hope he doesnt come after your folks though - fingers crossed he just pisses off to live under a rock.