Does the woman incur sin for severing ties with her nephew who assaulted one of her sons and cut off relations with her for more than five years, or is he the one who is obligated to visit her, and must she initiate visiting him and greeting him?

There is no doubt that both the paternal aunt and her nephew have rights upon each other. His severance of ties with her exposes him to Allah's wrath, as she is a kin and a neighbor to him. Her right upon him stems from three aspects: religion, kinship, and neighborliness. However, it is not permissible for the paternal aunt to respond to his wrongdoing with wrongdoing, as her severance of ties with him is also forbidden, given that he is a kin and a neighbor. Therefore, she must initiate reconciliation and mend the relationship, because cutting off kinship ties is one of the greatest prohibitions, and Allah has cursed those who sever their kin. The true maintainer of ties is he who connects with those who cut him off and does good to those who harm him, not one who reciprocates good with good. By doing so, she will earn Allah's pleasure and aid, and Allah will increase her in honor and humility.