My master A’lā Ḥaḍrat, Imām-e-Aĥl-e-Sunnat, scholar of Sharī’aĥ, guide of Ṭarīqaĥ, ‘Allāmaĥ Maulānā Ash-Shāĥ Imām Aḥmad Razā Khān عَـلَيْهِ رَحْمَةُ الـرَّحْمٰن said: Excluding the relatives that a woman is prohibited to marry due to a blood-relation, it is neither Wājib nor prohibited for her to observe veil with men whom she can never marry as a result of the relation formed by Raḍā’at. These people include the father, grandfather, brother, nephew, uncle, son, grandson [all through Raḍā’at as well as relatives through marriage (Muṣāĥarat) such as the father in law, mother-in-law, son-in-law, daughter-in-law (it is permissible whether to observe or not to observe veil with them)].
Even though it is not incumbent for her to observe veil in these cases but it is appropriate to observe veil if she is young or there is a possible risk of mischief, especially if a man and woman are related through Raḍā’at because people usually do not consider this relation something to be very important. (Fatāwā Razawiyyaĥ, vol. 22, pp. 235)
Which people are included in the category of Maḥārim blood relatives
Answer: These consist of four types of relatives:
1. One’s children (i.e. son and daughter), grandchildren, great-grand children and so on.
* Raḍā’at implies relationship formed on the basis of breastfeeding a baby under certain conditions. See its details in Baĥār-e-Sharī’at.