Narrated Buraydah: The Prophet ﷺ appointed a sixth to a grandmother if no mother is left to inherit before her.
Related hadith on this topic
Explanation & Benefits
Shaykh Umar Farooq Saeedi
Benefits and Issues:
The chain of narration is weak, and the ruling is as follows: the mother’s mother (paternal grandmother) and the maternal grandmother are subject to a barrier (hajib) — meaning, they are deprived of their right to inheritance.
Source: Sunan Abu Dawood – Commentary by Shaykh Umar Farooq Saeedi, Page: 2895