How should one deal with a sister who feels extreme guilt and constantly blames herself for her shortcomings in serving her deceased mother, and visits the grave daily believing that this will make her mother forgive her?

We advise patience, piety, and refraining from weeping and mourning, and for women not to visit graves frequently unless there is a need. We also advise frequent supplication for your mother, maintaining ties with her relatives and friends, and giving charity on her behalf. If possible, ongoing charity is better, for the Prophet, peace and blessings be upon him, said: "When a person dies, all his deeds cease except for three: ongoing charity, knowledge from which benefit is derived, or a righteous child who prays for him."