What is the way to deal with a father who repeatedly rejects his son's marriage and demands that he divorce after the marriage has taken place, and prevents his other children from communicating with him?

A father's preventing his adult son from marrying is forbidden (haram), and he is sinful for his action, especially if the son falls into sins because of it. The father's prohibition is not obligatory to obey, and the son is not considered disobedient (aqq) for disobeying him.

Likewise, it is not permissible for a father to force his son to marry someone he does not desire, nor is the son obliged to divorce his wife if his mother orders him to do so. This is not considered part of honoring one's parents (birr al-walidayn).

However, the son erred by speaking harshly to his father, for the father's right is great.