What is the ruling of Islamic law concerning dealing with a father who is addicted to women, alcohol, and gambling, who curses Allah and beats the mother and refuses her treatment, does not pray and prevents his children from going to the mosque, and wants his son to spend on him, knowing that the father spends money on forbidden things?

If what was mentioned about the father is true—that he beats and harms the mother and slanders her, does not provide for the youngest son, engages in illicit relationships, drinks alcohol, wastes money, curses and slanders the son and disowns him, and curses the Exalted Lord—then these are grave evils.

Nevertheless, he remains the father, and the son must honor him and treat him kindly, even if he is a disbeliever, as Allah Almighty says: "But if they endeavor to make you associate with Me that of which you have no knowledge, do not obey them but accompany them in [this] world with appropriate kindness."

Among the forms of kindness to him is striving to reform him through sincere advice or by involving someone who can influence him, and frequently supplicating for his repentance and guidance. The father has a right to his son's money for what he needs, without harming the son. Money must be given to him if he is in need, even if it is probable that he will use it for unlawful purposes, as the son is not obligated to investigate that. A father's supplication against his son unjustly will not be answered by Allah, and the son should avoid the causes of his father's anger as much as possible.