The following is based on a question I wrote in the margin of my chumash about ten years ago.
וַנֹּאמֶר אֶל אֲדֹנִי לֹא יוּכַל הַנַּעַר לַעֲזֹב אֶת אָבִיו וְעָזַב אֶת אָבִיו וָמֵת
And we said to my lord, 'The boy cannot leave his father, for if he leaves his father, he will die.
Question 1) Is it true that the brothers had said that? In the Torah's account of Yosef's two previous conversations with his brothers (Gen. 42:9-20), in Parashat Miketz, there's no mention of the brothers making any objection. Likewise, in their account to Ya'akov of their first trip to Egypt (Gen. 42:30-34), they don't mention having raised any objection.
In Rashi's commentary on this verse (based on Targum Yonatan), he inteprets the last "he" as referring to Binyamin:
אם יעזוב את אביו דואגים אנו שמא ימות בדרך, שהרי אמו מתה בדרך
If he leaves his father, we are worried lest he die on the way, for his mother died on the way.
Question 2) Why interpret this "he" as referring to Binyamin and not to Ya'akov - that if Binyamin leaves his father, his father will die?
See Gen. 43:38, when Ya'akov forbade bringing Binyamin down as follows:
וַיֹּאמֶר לֹא יֵרֵד בְּנִי עִמָּכֶם כִּי אָחִיו מֵת וְהוּא לְבַדּוֹ נִשְׁאָר וּקְרָאָהוּ אָסוֹן בַּדֶּרֶךְ אֲשֶׁר תֵּלְכוּ בָהּ וְהוֹרַדְתֶּם אֶת שֵׂיבָתִי בְּיָגוֹן שְׁאוֹלָה
But he (Jacob) said, "My son shall not go down with you, because his brother is dead, and he alone is left, and if misfortune befalls him on the way you are going, you will bring down my gray head in sorrow to the grave."
It sounds like he's afraid that something will happen to Binyamin, but certain that the result of such would be a heartbroken death for himself. The certain language of "he will die" seems to me to fit more with the latter.
There is similar language later that Rashi interprets differently. In Gen. 44:31, Yehuda reiterates:
וְהָיָה כִּרְאוֹתוֹ כִּי אֵין הַנַּעַר וָמֵת וְהוֹרִידוּ עֲבָדֶיךָ אֶת שֵׂיבַת עַבְדְּךָ אָבִינוּ בְּיָגוֹן שְׁאֹלָה
it will come to pass, when he sees that the boy is gone, he will die, and your servants will have brought down the hoary head of your servant, our father, in grief to the grave.
There is a similarly ambiguous "he will die" here, but here, Rashi says that it refers to Ya'akov:
His father will die because of his calamity [of the loss of his son].
Why does Rashi intepret this ambiguity the way I would have expected, but not the previous one?