Choosing the younger – Vayyechi

Jacob on his deathbed, by Jan Victors c.1635
By this week’s sidra the narrative focusses on grandchildren, though Menasseh and Ephraim are not the only grandsons to be mentioned in B’reshit.
Grandfather Jacob wants to give a blessing and decides that the younger son deserves it.
Joseph reminds his father that Menasseh is the older, not Ephraim. “I know, my son, I know,” says Jacob.
We expect the two boys to argue over Jacob’s plan. Strangely, no argument takes place: the long chain of family quarrels is over and the two boys accept their grandfather’s choice.
What is Jacob’s motivation? As a younger son himself he knows that older sons – for all their good points – are sometimes unfitted to bear the responsibility of spiritual leadership.
His hand of blessing chooses the more suitable son.