Walī is her father. If she does not have a father then her grandfather is her Walī. If she has a son, then he is the most preferred Walī. If she does not have a son then her grandson and then great-grandson will be her Walī and so on. After that, her father, then grandfather, and then great-grandfather will be her Walī. In his presence, no one else can be her Walī, even if he is her great-great-grandfather and so on.
Question: Who is the Walī if any of these five relatives are not present? Can the mother be a Walī too?
Answer: After these five relatives, the Walī is the brother, then the father’s brother and then those children of the father’s brother who are ‘Aṣabaĥ relatives will become Walī with their details. For further details, please see Baĥār-e-Sharī’at, part 7, page 43 published by Maktaba-tul-Madīnaĥ. If there are no relatives in the list of ‘Aṣabaĥ bi-Nafsiĥī then the mother is the Walī. If there is no mother, then the paternal-grandmother and then the maternal-grandmother etc. is the Walī. There is a long list of relatives which can be seen in Baĥār-e-Sharī’at, part 7, page 42 to 52.
Question: What is ‘كُفۡو’ (Kufw)?
Answer: In common language, anyone of the same race is referred to as ‘كُفۡو’ (Kufw) but, in Sharī’aĥ, a Kufw is a man who is not so much inferior to a woman in lineage, religion, occupation, behaviour, or anything else that if he married her it would publicly disgrace and embarrass the woman’s Walīs (her father, grandfather etc.).
(Fatāwā Malik-ul-‘Ulamā, pp. 206)