What's the ruling if my father never took care of me?

Assalamu alaikum, I'm the youngest of three. My father was around for my older sisters, but not for me; I don't remember him. He used to be abusive toward my mother, and now he has another family in Germany or something-I don't really know much about his life. It's not like he hates me; my mother, I'd say she 'left' because he wasn't a good person. So if I tried to rebuild a relationship with him, I honestly think I could, but the thing is, I really don't want to. He's shown he doesn't care about me, and he used to harm my family. Is it still my duty to treat him with kindness? PS: My family isn't Muslim, but I reverted.