Will the prayers, fasting, and deeds of the questioner sister be accepted despite her sister boycotting her, her sister's intense hatred for her, her complete refusal of any reconciliation, and her tarnishing of her reputation, knowing that the mother cannot do anything?

Islam has encouraged maintaining ties of kinship and affection and warned against severance, as Allah Almighty says: "And those who join that which Allah has commanded to be joined," and His saying: "So, would you perhaps, if you turned away, cause corruption in the land and sever your ties of kinship? Those are the ones whom Allah has cursed, so He made them deaf and blinded their vision." You should strive for reconciliation with your sister calmly. The true maintainer of kinship ties is one who maintains them even if they are severed by others. The Prophet, peace and blessings be upon him, said: "The one who maintains ties of kinship is not the one who reciprocates, but the one who maintains ties of kinship is he who maintains ties when they are cut off." A Muslim should initiate reconciliation and peace because deeds are presented to Allah, and He forgives everyone who does not associate anything with Allah, except for one who has animosity between him and his brother until they reconcile. If you exert your utmost effort for reconciliation, Allah will not let your reward be lost, for He Almighty says: "Indeed, We do not allow to be lost the reward of the reformers," and "Allah does not burden a soul beyond its capacity." The sin then remains upon the one who refuses reconciliation.