Is the father's dry treatment of his children, which leads to their alienation and disharmony, considered disobedience?

If the question is about the father's behavior, then this is not considered 'Uquq (disobedience to parents) in Islamic law. And if you dislike his actions without harming him, then this is not 'Uquq from you towards your father. Affection and good companionship should prevail in the family, and parents should be moderate in their dealings with their children. The father can be gently confronted with sincerity at a time of his calmness. And assuming his behavior persists, this does not nullify his right to kindness, good treatment, and obedience in what is right. This matter should not distract you from what benefits you.