What is the best way to deal with a mentally ill neighbor?

Omg....my neighbor downstairs does the same thing but I just mind my business because she fights him too. The way I see is she must love being beat because she keeps coming back and even when she lost her kids and he was removed from the house and CPS gave them in home couseling she still let him move back in and voilate the restraining order. I speak to them both when they speak to him and when they fight I turn up my music or tv and just ignore it. Mind your business and stay out of their business, that's all you can do.