Is it permissible to help a brother who is a drunkard with money for his failed business, which failed due to his addiction, and he is now in need of money?

It is not permissible to help a man who went bankrupt in his business because he spent his money on drinking alcohol, if it is highly probable that he will use the money for unlawful purposes. This is because it would constitute aiding in sin, and Allah Almighty says: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression."