✅Answer:

1 حفص بن البختري عن أَبي عبداللَّه في الرَّجُل يَمُوتُ و عَلَيْه صَلَاةٌ أَو صِيَامٌ قال يَقْضِي عَنْهُ أَوْلَى النَّاسِ بِمِيرَاثِهِ قُلْتُ فَإِنْ كَان أَوْلَى النَّاس بِهِ امْرَأَةً فقال لا إِلَّا الرِّجَالُ

📚Al-Kafi, Vol. 4, p. 123

Imam Sadiq (peace be upon him) said about a person who dies and has prayers and fasts that he owes: 'The person most entitled to his inheritance performs them on his behalf.'

I said: 'What if the person most entitled to him is a woman?' He said: 'No, only men!'

2 عن أبي عبدالله قال: سَأَلْتُهُ عن الرَّجُلِ يَمُوتُ و عَلَيْهِ دَيْنٌ مِنْ شَهْرِ رَمَضَان مَنْ يَقْضِي عَنْهُ قال أَوْلَى النَّاسِ بِهِ قُلْتُ و إِنْ كَانَ أَوْلَى النَّاسِ بِهِ امْرَأَةً قَالَ لَا إِلَّا الرِّجَال

📚Al-Kafi, Vol. 4, p. 124

The narrator said: I asked Imam Sadiq (peace be upon him) about a person who dies and has a debt of Ramadan fasts on him, who should perform them on his behalf?

He said: 'The person most entitled to him!'

I said: 'Even if the person most entitled to him is a woman?'

He said: 'No, only (from) men.'

3 قد روي عن الصَّادِق أَنَّهُ قال: إِذَا مَاتَ الرَّجُلُ وَ عَلَيْهِ صَوْمُ شَهْرِ رَمَضَان فَلْيَقْضِ عَنْهُ مَنْ شَاءَ مِنْ أَهْلِهِ

📚Al-Faqih, Vol. 2, p. 153

Imam Sadiq (peace be upon him) said: 'When a person dies and he has Ramadan fasts on him, then any of his family who wishes may perform them on his behalf!'

4 قال: كَتَبْتُ إِلَى الْأَخِيرِ رَجُلٌ مَاتَ وَ عَلَيْهِ قَضَاءٌ مِنْ شَهْرِ رَمَضَان عَشَرَةُ أَيَّامٍ و لَهُ وَلِيَّانِ هَلْ يَجُوزُ لَهُمَا أَنْ يَقْضِيَا عَنْهُ جَمِيعاً خَمْسَةَ أَيَّامٍ أَحَدُ الْوَلِيَّيْنِ وَ خَمْسَةَ أَيَّامٍ الْآخَرُ فَوَقَّعَ يَقْضِي عَنْهُ أَكْبَرُ وَلِيَّيْهِ عَشَرَةَ أَيَّامٍ وِلَاءً إِنْ شَاءَ اللَّهُ

📚Al-Kafi, Vol. 4, p. 124

Saffar said: I wrote to Imam Askari (peace be upon him): 'A person dies and has missed Ramadan fasts, and he has two guardians. Is it permissible for both of them to perform them, one of them 5 days and the other also 5 days?'

The Imam wrote: 'The older of the two guardians performs ten days consecutively on his behalf. If Allah wills.'

5 أَبي بصير قال: سَأَلْتُ أَباعبداللَّه عن رَجُلٍ سَافَرَ في شَهْرِ رَمَضَانَ فَأَدْرَكَهُ الْمَوْتُ قَبْلَ أَنْ يَقْضِيَهُ قَالَ يَقْضِيهِ أَفْضَلُ أَهْلِ بَيْتِه

📚Al-Tahdhib, Vol. 4, p. 325

Abu Basir said: I asked Imam Sadiq (peace be upon him) about a person who travels in the month of Ramadan and death overtakes him before he performs the missed fasts; he said: 'The best of his family performs them on his behalf!'

6 'an al-sadiq fi al-rajul yamutu wa 'alayhi salat aw sawm qala yaqdihi awla al-nas bihi

📚Bihar, Vol. 88, p. 310

Imam Sadiq (peace be upon him) said about a person who dies and has prayers or fasts on him: 'The person most entitled to him performs them on his behalf!'

7 عن الصادق قال: الصَّلَاةُ الَّتِي دخل وَقْتُهَا قَبْلَ أَنْ يَمُوتَ الْمَيِّتُ يَقْضي عَنْهُ أَوْلَى النَّاس بِهِ

📚Bihar, Vol. 88, p. 313

Imam Sadiq (peace be upon him) said about a prayer for which the time had come before the deceased's death: 'The person most entitled to him performs it on his behalf!'

8 wa idha mata rajul wa 'alayhi sawm shahr ramadan fa-'ala waliyyihi an yaqdiya 'anhu wa kadhalika man fatahu fi al-safar aw al-marad illa an yakun mata fi maradihi min qabli an yasihha fala qada'a 'alayhi idha kana kadhalika wa idha kana lil-mayyit waliyyan fa-'ala akbarihim min al-rijal an yaqdiya 'anhu, wa in lam yakun lahu wali min al-rijal qada 'anhu waliyyuhu min al-nisa

📚Al-Muqni', p. 63

Sheikh Saduq in his book 'Al-Muqni',' whose contents he considers to be from the narrations of the Shi'a elders with the chain of transmission removed, said: 'When a person dies and has Ramadan fasts on him, it is on his guardian to perform them on his behalf, and likewise for one who missed them in travel or illness, except if he died in his illness before he recovered, in which case there is no missed fast on him if it was like that. And if the deceased has two guardians, it is on the elder of the two men to perform them on his behalf, and if he has no male guardian, his female guardian performs them on his behalf!'

✅In the above narrations and others, it is clear that the missed prayers and fasts of the deceased must be performed by the person most entitled to his inheritance from among the men.

However, in the absence of a male heir and the guardian being exclusively a woman, although the obligation of performance is not explicit for women, but considering the command to perform the fasts in the absence of a male guardian in hadith 8 and the generalities mentioned in hadith 3 and the like, if the female guardian of the deceased performs the prayers and fasts of the deceased, she has acted with precaution and has cleared the debt of prayers and fasts from the deceased, and if Allah wills, it will be a cause for ease in the deceased's afterlife.

Performing missed prayers and fasts of the deceased