If a biological father has little to do with his biological offspring, and instead spends most of his time with his sister’s children who call him by a term meaning "father" rather than "uncle," the descent system of these people is most likely Matrilineal.
Step-by-step explanation:
Matrilineal is made up of two words ‘Matri’ means mother ‘lineal’ means link or ancestry. So matrilineal means the generation of people that origin or come before a person i.e. female. Matrilineal means maintaining the generation through the mother-line rather than father-line.
In matrilineal family relationship can be record through female. Tradition that that follows to give mother last name to children is a matrilineal tradition. This type of tradition is found in countries like Ghana, Indonesia, Cameroon, Malaysia, Costa Rica, and India etc. Akon, Alor, Betek, Bribri, Billava, Garo are some groups that follows the matrilineal tradition.