What is your advice to a person who wrongs people, insults them, and slanders their honor, is negligent in his prayers, and drinks intoxicants, with his relatives having despaired of his reform?

The psychological state of the errant individual must be considered when advising him, and various methods of da'wah (invitation to Islam) and gentleness should be employed, just as the Prophet, peace and blessings be upon him, did with the Bedouin who urinated in the mosque and the young man who sought permission to commit adultery. He can be reminded of the punishment for violating people's honor and the danger of neglecting prayer and intoxicants. Advice can also be given through trusted friends. If these methods fail, then avoidance (boycotting) or depriving him of what he needs can be used, or informing the authorities if that would be beneficial in deterring him, while consulting with scholars and people of sound judgment.