Messenger of Allah ﷺ said, "Whoever died and he ought to have fasted (the missed days of Ramadan) then his guardians must fast on his behalf."  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ مَنْ مَاتَ وَعَلَيْهِ صِيَامٌ صَامَ عَنْهُ وَلِيُّهُ  

A man came to the Prophet ﷺ and said, "O Messenger of Allah ﷺ! My mother died and she ought to have fasted one month (for her missed Ramadan). Shall I fast on her behalf?" The Prophet ﷺ replied in the affirmative and said, "Allah's debts have more right to be paid." In another narration a woman is reported to have said, "My sister died..." Narrated Ibn ʿAbbas: A woman said to the Prophet ﷺ "My mother died and she had vowed to fast but she didn't fast." In another narration Ibn ʿAbbas is reported to have said, "A woman said to the Prophet, "My mother died while she ought to have fasted for fifteen days."  

جَاءَ رَجُلٌ إِلَى النَّبِيِّ ﷺ فَقَالَ يَا رَسُولَ اللَّهِ إِنَّ أُمِّي مَاتَتْ وَعَلَيْهَا صَوْمُ شَهْرٍ أَفَأَقْضِيهِ عَنْهَا قَالَ نَعَمْ قَالَ فَدَيْنُ اللَّهِ أَحَقُّ أَنْ يُقْضَى قَالَ سُلَيْمَانُ فَقَالَ الْحَكَمُ وَسَلَمَةُ وَنَحْنُ جَمِيعًا جُلُوسٌ حِينَ حَدَّثَ مُسْلِمٌ بِهَذَا الْحَدِيثِ قَالاَ سَمِعْنَا مُجَاهِدًا يَذْكُرُ هَذَا عَنِ ابْنِ عَبَّاسٍ وَيُذْكَرُ عَنْ أَبِي خَالِدٍ حَدَّثَنَا الأَعْمَشُ عَنِ الْحَكَمِ وَمُسْلِمٍ الْبَطِينِ وَسَلَمَةَ بْنِ كُهَيْلٍ عَنْ سَعِيدِ بْنِ جُبَيْرٍ وَعَطَاءٍ وَمُجَاهِدٍ عَنِ ابْنِ عَبَّاسٍ قَالَتِ امْرَأَةٌ لِلنَّبِيِّ ﷺ إِنَّ أُخْتِي مَاتَتْ وَقَالَ يَحْيَى وَأَبُو مُعَاوِيَةَ حَدَّثَنَا الأَعْمَشُ عَنْ مُسْلِمٍ عَنْ سَعِيدٍ عَنِ ابْنِ عَبَّاسٍ قَالَتِ امْرَأَةٌ لِلنَّبِيِّ ﷺ إِنَّ أُمِّي مَاتَتْ وَقَالَ عُبَيْدُ اللَّهِ عَنْ زَيْدِ بْنِ أَبِي أُنَيْسَةَ عَنِ الْحَكَمِ عَنْ سَعِيدِ بْنِ جُبَيْرٍ عَنِ ابْنِ عَبَّاسٍ قَالَتِ امْرَأَةٌ لِلنَّبِيِّ ﷺ إِنَّ أُمِّي مَاتَتْ وَعَلَيْهَا صَوْمُ نَذْرٍ وَقَالَ أَبُو حَرِيزٍ حَدَّثَنَا عِكْرِمَةُ عَنِ ابْنِ عَبَّاسٍ قَالَتِ امْرَأَةٌ لِلنَّبِيِّ ﷺ مَاتَتْ أُمِّي وَعَلَيْهَا صَوْمُ خَمْسَةَ عَشَرَ يَوْمًا