Does a sister from Raḍā`ah (breastfeeding) inherit?
The answer
The laws of inheritance are one of the most explicit set of laws in the Qur’ān. They have been mentioned in Sūrah al-Baqarah, Sūrah al-Nisā’ and Sūrah al-Mā’idah.
In short: a sister through breastfeeding does not inherit.
Explanation
There are three factors which make a person eligible to receive a share from an estate:
1) Blood and consanguinity kinship
2) Marital relationship
3) Allegiances (for freed slaves)
There are different types of heirs who potentially can inherit depending on a number of factors:
1) Dhawī al-Furūḍ (Those entitled to prescribed shares) such as the father, mother, husband, wife, daughter and a few others.
2) `Aṣabah (Residuaries) such as the son, grandson, father, grandfather, real brothers and sisters, consanguine brothers and sisters and a few others.
3) Dhawī al-‘arhām (distant kindred) are those blood relations who are neither sharers nor residuaries.
If the above types of heirs are non-existent, there are other entities who have the potential to inherit such as a freed slave, a person whose kinship had been confessed to by the deceased, a legatee bequeathed more than one-third and finally the public treasury through the process of escheat.
However, relationship formed through Raḍā`ah does not entitle one to a share in an estate.1
And Allah knows best.
Mufti Faraz Adam
References
1وَيُسْتَحَقُّ الْإِرْثُ بِإِحْدَى خِصَالٍ ثَلَاثٍ: بِالنَّسَبِ وَهُوَ الْقَرَابَةُ، وَالسَّبَبِ وَهُوَ الزَّوْجِيَّةُ، وَالْوَلَاءِ وَهُوَ عَلَى ضَرْبَيْنِ: وَلَاءُ عَتَاقَةٍ وَوَلَاءُ مُوَالَاةٍ وَفِي كُلٍّ مِنْهُمَا يَرِثُ الْأَعْلَى مِنْ الْأَسْفَلِ وَلَا يَرِثُ الْأَسْفَلُ مِنْ الْأَعْلَى إلَّا إذَا شَرَطَ فَقَالَ: إنْ مِتُّ فَمَالِي مِيرَاثٌ لَك؛ فَحِينَئِذٍ يَرِثُ الْأَسْفَلُ مِنْ الْأَعْلَى، كَذَا فِي خِزَانَةِ الْمُفْتِينَ.
وَالْوَارِثُونَ أَصْنَافٌ ثَلَاثَةٌ: أَصْحَابُ الْفَرَائِضِ وَالْعَصَبَاتُ وَذَوُو الْأَرْحَامِ، كَذَا فِي الْمَبْسُوطِ وَالْمُسْتَحَقُّونَ لِلتَّرِكَةِ عَشَرَةُ أَصْنَافٍ مُرَتَّبَةٌ، كَذَا فِي الِاخْتِيَارِ شَرْحِ الْمُخْتَارِ فَيُبْدَأُ بِذِي الْفَرْضِ ثُمَّ بِالْعَصَبَةِ النِّسْبِيَّةِ ثُمَّ بِالْعَصَبَةِ السَّبَبِيَّةِ وَهُوَ مَوْلَى الْعَتَاقَةِ، ثُمَّ عَصَبَةِ مَوْلَى الْعَتَاقَةِ ثُمَّ الرَّدِّ عَلَى ذَوِي الْفُرُوضِ النِّسْبِيَّةِ بِقَدْرِ حُقُوقِهِمْ، ثُمَّ ذَوِي الْأَرْحَامِ ثُمَّ مَوْلَى الْمُوَالَاةِ ثُمَّ الْمُقَرُّ لَهُ بِالنَّسَبِ عَلَى الْغَيْرِ بِحَيْثُ لَمْ يَثْبُتْ نَسَبُهُ بِإِقْرَارِهِ مِنْ ذَلِكَ الْغَيْرِ إذَا مَاتَ الْمُقِرُّ مُصِرًّا عَلَى إقْرَارِهِ، كَمَا لَوْ أَقَرَّ بِأَخٍ أَوْ أُخْتٍ وَمَا أَشْبَهَ ذَلِكَ ثُمَّ الْمُوصَى لَهُ بِجَمِيعِ الْمَالِ ثُمَّ بَيْتِ الْمَالِ، كَذَا فِي الْكَافِي. (الفتاوى الهندية ج 6 ص 447 الرشيدية)
فتاوى حقانية ج 6 ص 536
Based on the Hanafi school and on the question as it was asked. Another mufti may reach a different conclusion. Read the disclaimer.