How can a father's heart be softened regarding his dispute with his brother over land boundaries, and must he be obeyed in his commands and prohibitions related to this conflict?

The father's heart can be softened by reminding him of the virtues of maintaining kinship ties, and that severing them exposes one to punishment in this world and the hereafter. This can be supported by prophetic hadiths such as: "Whoever believes in Allah and the Last Day, let him maintain his ties of kinship," and "Whoever wishes that his provision be increased and his lifespan be extended, let him maintain his ties of kinship," and "The womb (kinship) is suspended from the Throne, saying: 'Whoever connects me, Allah connects him; and whoever severs me, Allah severs him.'" The reminder should be gentle and kind, while emphasizing filial piety towards the father, unless he commands disobedience; for there is no obedience to a creature in disobedience to the Creator.