How is maintenance divided between a paternal grandmother ('umm uloom) and a maternal grandmother ('umm ab)?
General Chapter
Al-Mughni
Book of Maintenance (Nafaqāt)
Primary text
The paternal grandmother and the maternal grandmother are equal concerning maintenance liability because they are equal in their inheritance shares.
Supporting text
For those who do not mandate maintenance upon anyone outside the direct lineage ('amood al-nasab), the entire maintenance obligation falls upon the grandmother.