What is the ruling on a brother shunning his brother who made a mistake, then apologized and desired for their relationship to return to its previous state?

Estrangement between Muslims is not permissible for more than three nights, based on what Anas ibn Malik, may Allah be pleased with him, narrated from the Messenger of Allah, peace and blessings be upon him, who said: "Do not hate one another, do not envy one another, do not turn away from one another, and be servants of Allah as brothers. It is not lawful for a Muslim to forsake his brother for more than three nights." Some scholars made an exception for forsaking people of innovation and desires, unless they show repentance.

Abu Hurairah narrated from the Prophet, peace and blessings be upon him, that he said: "It is not lawful for a believer to forsake another believer for more than three days. If three days pass, and he meets him, he should greet him with salam. If he returns the salam, they both share in the reward. If he does not return it, he bears the sin." Another hadith (definition) states: "Whoever forsakes for more than three days and dies, enters the Fire." And "Whoever forsakes his brother for a year is like one who sheds his blood." Furthermore, the deeds of people are presented to Allah on Mondays and Thursdays. Allah forgives every servant who does not associate anything with Him, except for those who are quarreling. It is said: "Leave these two until they reconcile." Therefore, a Muslim must repent from estrangement and initiate reconciliation, even if the other party continues the estrangement. A Muslim should offer greetings of peace, visit his sick brother, and fulfill all his rights.