Is forgiving the brother and his wife after a dispute, and the sister's effort to reconcile between siblings, considered a loss of the sisters' dignity or a religious duty?

Forgiveness and pardon for a sibling's harm, and upholding kinship ties, are acts that align with the ethics of Islam, and Allah and His Messenger have commanded them. Indeed, whoever forgives, their reward is with Allah, and Allah will increase them in honor. This was the character of the Prophet, peace be upon him, and Yusuf, peace be upon him. What the questioner did is better than the stance of her sisters, because it is a great door to acts of obedience such as maintaining kinship ties and reconciling disputes, which is superior to the rank of fasting, prayer, and charity. Her effort to reconcile between her siblings is among the best deeds and the most sublime acts of devotion to Allah.