Is the money earned by a father from his club, where weddings are held banning intoxicants and dancers, but he cannot prevent music or mixing due to the wishes of the wedding party, considered unlawful money?

It is not permissible for your father to lease the club for the purpose of committing sins, such as unlawful mixing, because that falls under cooperation in sin and aggression, which the Quran has prohibited. Scholars such as Ibn Baz and Al-Uthaymeen have issued fatwas (religious edicts) prohibiting taking compensation for anything unlawful, whether through sale or lease. Therefore, whoever leases their place for an unlawful matter, or for both lawful and unlawful benefits, has aided in disobedience and consumed ill-gotten wealth. In the case of mixing lawful and unlawful benefits, the unlawful portion is prohibited, and one must dispose of this unlawful part by spending it on charitable causes.