Would have things been different had i poisoned him when I still had the chance

I grew up with the most terrible father ...he was an alcoholic, he lost his job ...he would stay home all day , steal houshold things , sell to get beer , sleep with maids and verbally abuse all of us ...he once tried to pour hot oil on me when I tried to speak up against his injustice ...we had to sleep at the police station that night cause they weren't ready to help us ...they only accompanied us back home after 3 am and even then they didn't arrest him ...they just threatened him and he got out of our life for like a year ....he recently came back and he is back to his antics ....he steals even from personal bags now ...when he get drunk he loses all sense and literally can't even distinquish between the lounge and bathroom ..he pees everywhere and we as children have to excuse him ...I moved to another country to study ....I left my mom and baby brother behind ...my mom is sending me a message that he has started again ...he started shouting and being all violent and she had to rush out with my baby brother ...he locked the gate and now they can't come in....it's sometime after 12 back home....and they are still outside ...anything can literally happen to them ...I have prayed for my father's death more times than I can count ...does it make me a bad person....why doesn't he care about his family ...okay we can say he doesn't care about my mother bt what about his son ...they are literally going to sleep in the car tonight ....ita not safe for them....worst thing is this time I am not even home ....I feel sooo helpless....my mother is really stressed....she has angina ....if it gets too much anything can literally happen ....I'm helpless ....I'm frustrated ....I'm tired of such a life ....if God is really there then why does he let these things happen to my family