Well, personally, I would use all sorts of unprintable language. Or the Clint Eastwood cold scare mentioned above.

Unfortunately they have hit you at your weak point. I loathe people who do that. I hope you can get away from them, but if they live with you, well, F is for Family as the saying goes. You need to take the high road and walk away and take care of yourself. Once when I was a teenager I punched my sister instead of walking away when she was being a total psycho jerk, when she lived with me. It didn't do any longterm damage or even leave a temporary mark, but it scared her and I should have just walked away, left the building. So at least I learned from that and never hit anyone again. You have to take the high road and console yourself you have done the right thing, because they may never change.