Mental harassment and threat to do suicide

My father is alcoholic and I don't like this it's makes me angry due to this I try to beat him but my mother comes between me and him and makes me to stop she doesn't even let me call police instead of it she threats me that she will commit suicide or tells me that she will settle everything the next day when my father becomes sober but she just get angry on him and he say sorry but then after few months the same story repeats. And this is happening since my childhood and now I can't tolerate this anymore now how can I get help from law also I want to tell you that tonight she have said that she will add poison in everyone's food so there is threat to my life. Please help me soon