What is the ruling on the money that a brother used to send to his mother and sisters, and is the money resulting from his partnership with his brother in a halal project considered halal?

Selling alcoholic substances and owning nightclubs are forbidden, and one must repent from that. Your brother's repentance requires him to dispose of the ill-gotten money by spending it on the welfare of Muslims or on the poor and needy. If he becomes poor after disposing of it, he may benefit from it to the extent of his needs and the needs of his dependents until he finds a lawful alternative, because he has become one of the poor, and he may give it as charity to himself and his dependents if they are poor. As for your brother's mother and two sisters, if they are wealthy, or if your brother possesses lawful money that suffices them, then it is not permissible for him to spend on them from ill-gotten money, nor is it permissible for them to take it. However, if they are poor and he cannot find a lawful alternative for them, then there is no harm upon them in owning what their brother sends them from the ill-gotten money.