Is maintenance obligatory upon relatives by blood (Dhawu al-Arham) who belong to the main lines of lineage?

Primary text

Maintenance is obligatory upon relatives by blood who belong to the main lines of lineage, whether they are Dhawu al-Arham (like the mother's father or the daughter's son) or others, and whether they are blocked from inheritance or are actual heirs. This is the established position of Al-Shafi'i. This ruling is established because their kinship is considered a partial and substantive kinship, which necessitates acceptance of testimony and prevents retaliation (Qisas) against a father for killing a son, thus mandating maintenance in all circumstances, similar to the relationship with the immediate paternal relatives.