"what there shall be to him": We are hereby taught that the son inherits what is anticipated as well as what is on hand.
"he shall not grant primogeniture": We are hereby taught that he is not permitted to grant it. I might think that he is not permitted to do so, but if he did so, it stands; it is, therefore, written "he shall not be able to grant primogeniture," (the implication being that) if he does, it shall not stand.
"… over the face of the son of the hated one": We are hereby taught that if his head or most of it emerged live (from the womb), he negates the next birth as a first-born.