Will a person whose earnings were unlawful in this world be punished by having calamities afflicted upon them, such as illness befalling their family members or their child becoming corrupt, leading them to spend that money on their treatment or on corrupt endeavors?

Unlawful wealth is devoid of blessing, and both it and any lawful wealth mixed with it are exposed to ruin and disappearance. Allah does not accept charity, Hajj, or maintaining kin ties from it. Rather, its owner endures its hardships, bears its accountability, and suffers its torment. Allah Almighty addresses those who deal in usury: "And if you do not, then be informed of a war [against you] from Allah and His Messenger." (Al-Baqarah: 279), and He says: "And none knows the soldiers of your Lord except He." (Al-Muddaththir: 31).

As for the Hereafter, the matter is more severe. Allah Almighty says: "The Fire will sear their faces, and they will be therein grimacing." (Al-Mu'minun: 104). If punishment is delayed for some people in this world, it may be a gradual enticement. Allah Almighty says: "And I will give them time. Indeed, My plan is firm." (Al-Qalam: 45), and He says: "And We only extend it to them so that they may increase in sin, and for them is a humiliating punishment." (Al 'Imran: 178).

Whoever is afflicted with some unlawful wealth must repent from it and dispose of it by returning it to its rightful owners if possible. Otherwise, they should spend it on acts of piety and charity. For Allah forgives all sins. Allah Almighty says: "Say, 'O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful.'" (Al-Zumar: 53).