When appealing his fate, Yehuda pleaded: "If you do not let Binyomin return home, you will send my father's soul to the grave in sorrow..."
It would seem from Yehuda's presentation, that Binyomin was a tender, young boy, who still lived in his father's house. Yet, at the time of this episode, Binyomin was actually a grown man, married, and a father of ten sons. (Rashi, Bereshis, 43:29)
This being the case, Yehuda should have made a more powerful appeal, by invoking the sorrow of the young mother and ten children! Surely, the image of the large family in despair would elicit a more sympathetic judgement from the Second to the King. Why did Yehuda plea for Yosef to consider the father's sorrow instead?