There are no records of a human having been intentionally kept awake long enough to kill them, but a hereditary disease called fatal familial insomnia suggests there is an ultimate limit.

没有关于一个人类被迫保持不睡的时间久到死亡的记录，但是有一种叫做致命性家族失眠症的遗传病似乎表明人类无睡眠时间是有极限的。

youdao

Results a total of 143 probable CJD cases (44.14%) and 15 possible CJD cases (4.63%), 10 genetic CJD cases (3.09%) and 8 fatal familial insomnia (FFI) cases (2.47%) were identified.

结果发现散发型克雅氏病临床诊断病例143例(44.14%)，疑似诊断病例15例(4.63%)，遗传型克雅氏病病例10例(3.09%)，致死性家族型失眠症8例(2.47%)。

youdao

Many of the doctor's descendants would experience similar symptoms in the course of dying from fatal familial insomnia, suggesting that the Venetian doctor may have been the earliest recorded case of a disease that has gone on to torment his relatives for more than two centuries.

NPR: Book Traces Family Suffering from Deadly Insomnia