mothers and grandmothers of boys live shorter lives because they too become worthless and expendable in the eyes of natural selection.
That's not how natural selection works.
the father's fetal DNA "fights" the mother for more resources during pregnancy
The father provides both X and Y chromosomes, creating both girls and boys. The father's DNA also creates the placenta, which is necessary for the fetus.
Fun fact: when the male fetus is about to be aborted (spontaneously or surgically), it immediately releases colossal quantities of male DNA into the woman's bloodstream, as a last ditch effort of sorts.
How would a fetus know it was about to be surgically aborted?