What should I do about my unveiled sisters who refuse to wear the hijab despite being reminded of the Qur’an, and my father refuses to compel them, given my extreme fear of being a dayyuth?

Every shepherd is responsible for his flock, and it is the duty of parents to fear Allah concerning their children and protect them from the Fire. Islam has forbidden tabarruj (displaying oneself) and mingling with non-mahram (definition) men because they are often companions to zina (fornication/adultery) and undermine honor. Gheerah (protective jealousy) is at the core of faith, and in the hadith (definition): "Indeed, Allah is jealous, and the believer is jealous." This is contrasted with the dayyuth, who condones wickedness among his family. The father is the primary person responsible for obliging his family to observe the Shar'i Hijab (definition) and modesty, safeguarding honor and society. Do not fall into dayyutha due to your hatred of this evil, but killing is not permissible. Rather, you must advise your family gently and kindly, provide them with Islamic materials, and supplicate for their guidance.