Is not allowing one's nephew to cheat on exams considered a squandering of his future, and will one be held accountable for the hardship that results from it? Will he receive the reward of "worship during times of tribulation is like migration to me" for refraining from cheating in an environment where it is widespread? And is it true that whoever cheats and takes the right of another in university admission will have from his good deeds taken away on the Day of Judgment?

The questioner's advice to his nephew to stop cheating in exams is a correct and rewardable act, and the nephew's response to the advice is also a good and rewardable act. His nephew's overall academic achievement and everything that results from it are part of Allah's divine decree and destiny, and it is commensurate with his level and effort. As for abandoning cheating, there is a reward for it from Allah, and this reward increases when evil is widespread. However, this does not fall under the virtue of "worship in times of turmoil" mentioned in the hadith, as that is specific to times of tribulation, fighting, and disorder. As for the statement that a cheater will have his good deeds taken away on the Day of Judgment, this is not definitive, as the cheater may repent, and Allah will judge between His servants with His knowledge and wisdom.