It's not quite that straightforward; since close kin also share genetic heritage anything you do to benefit your near kin also propagates some percentage of your own DNA. Kin selection has been part of evolutionary theory since Darwin:
> "This difficulty, though appearing insuperable, is lessened, or, as I believe, disappears, when it is remembered that selection may be applied to the family, as well as to the individual, and may thus gain the desired end."
Eusocial insects are doing quite well, for example, despite the tiny subset of the species that reproduce.
> "This difficulty, though appearing insuperable, is lessened, or, as I believe, disappears, when it is remembered that selection may be applied to the family, as well as to the individual, and may thus gain the desired end."
Eusocial insects are doing quite well, for example, despite the tiny subset of the species that reproduce.