An example of one cause with two aspects is where a person dies leaving behind his maternal brother, who is also his paternal cousin. That is, after his father died, his paternal uncle married his mother, and she bore him a son. This son is both a paternal cousin and a maternal brother. Thus, when this son dies, the other inherits from him through one cause—namely, blood relation—but it is a cause with two aspects: prescribed-share inheritance and residuary inheritance.
The discussion here concerns maintenance due to relatives, lest someone ask: “Must a wife support her husband if he is poor?” The answer is no. Our discussion concerns those whose maintenance is obligatory by reason of kinship.
An example of one who inherits by a prescribed share is a maternal brother, while an example of one who inherits as a residuary is a full brother. Thus, if a maternal brother is wealthy and his brother is poor, the wealthy brother must support the poor one. And if a full brother is wealthy and his brother is poor, maintenance is obligatory upon the wealthy brother.
His statement, “but not by kinship alone,” means: not one who inherits by kinship alone—that is, one who belongs to the category of distant kindred, such as a paternal aunt in relation to her nephew, a maternal aunt, a maternal uncle, and the like. No maintenance is due to them, even if they were to die of hunger—except by way of rescuing an inviolable life from destruction. Thus, your maternal uncle and a man to whom you have no relationship are equal in this regard: you are not obliged to support him, because he inherits by kinship alone, not by a prescribed share or as a residuary. This is the madhhab.
His statement, “apart from his direct ascendants and descendants,” refers to one’s ascendants and descendants. Their maintenance is obligatory even if they inherit by kinship alone. Thus, if the maternal grandfather is wealthy and the daughter’s son is poor, he must support his daughter’s son. Conversely, if the daughter’s son is wealthy, he must support his poor maternal grandfather.