How we cite our quotes:
Quote #4
"The father never speaks her name, the child does not know it" (1.3).
Not once in his entire life has the kid heard his father say his mother's name. The father probably blames the kid for her death, since she died while giving birth to him (the kid).
Quote #5
"He has a sister in the world that he will not see again" (1.3).
This is the only mention we get of anyone in the kid's family other than his father. And as the novel reminds us, this sister might as well not exist because the kid will never see her again once he runs away from home. This is something he has already accepted.
Quote #6
"All history present in that visage, the child the father of the man" (1.3).
Cormac McCarthy has a clever way of arguing that a child can be the father of a man. When you think about it, the kid character is a child before he grows up into a man. That means the child came first, which makes him the "father" of the man.