Is it permissible to boycott a father who harms his children and wife, and to discuss him with one's sister to relieve psychological pressure, and is that considered disobedience to parents?

Mere hatred of the father in the heart is not blameworthy as long as it is not accompanied by ill manners or disobedience. Allah has urged honoring parents and being good to them, and has forbidden disobeying them. Therefore, children must obey them even if the father is abusive. They must accompany them with kindness, show love and affection through words and deeds, and pray for them. As for complaining to one's sister about the father for the purpose of discussing how to deal with him and avoid his harm, this is permissible, because mere complaining and making a permissible request is not considered disobedience.