What can a woman do to honor her deceased father who was remiss in prayer, fasting, zakat, and Hajj, given her fear for him of the torment of the grave and the Day of Resurrection?

One can benefit their deceased parent through sincere supplication for them, as the Prophet, peace and blessings be upon him, said: "When a person dies, all his deeds come to an end except for three: an ongoing charity, knowledge from which others benefit, or a righteous child who supplicates for him." One can also give charity on their behalf, perform Hajj and Umrah for them, and pay off their debts. As for missed Ramadan fasts, Zakat payments, and prayers, no one can perform them on their behalf, except that Zakat is similar to a debt, so an estimation of what was not paid can be made and paid on their behalf.