You are a free individual, with no moral obligation to anyone else, as a first principle of legal philosophy and as an observable fact of life. Liberty is the cornerstone of justice. Justice is always done retail, one case at a time. It is done deliberately and slowly. It is every person's job to judge the facts of reality, separating truth from falsehood, right from wrong, giving each man his due.
Some men deserve our loyalty and service.
Some must be punished. We, each of us, do this privately, choosing lovers and friends on their evident merit, shunning others because they are evil assholes. But justice excuses no one. If dad is an asshole, he should be disowned. It is specifically evil to exempt someone from justice because he is a blood relative.