Is it permissible to help my brother from Zakat funds, knowing that he is wasteful, does not save, spends on entertainment and cigarettes, and does not pay his son's school fees? Does the principle "Your closest kin are most deserving of charity" apply to him despite his negligence and mismanagement of his financial affairs?

It is impermissible for a sister to give her Zakat to her brother if she knows or strongly believes that he will use it for something forbidden, because he is imprudent. This would be considered cooperation in sin and aggression, which is prohibited in His — Exalted be He — saying: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression."

However, if the man's dependents are in need and have educational expenses, it is permissible to give the Zakat to their mother so that she may use it to manage the affairs of her brother's household. By doing so, the questioner will be rewarded for giving Zakat to her brother's family.