Jami` at-Tirmidhi 718
جامع الترمذي#718Da'ifIbn Umar narrated that :the Prophet said: "Whoever died while he had a month to fast, then a needy person should be fed on his behalf in place of every day
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Ahmad Muhammad ShakirDaif
Al-AlbaniDaif
Zubair Ali ZaiDaif
In-book reference: 8:37