In the middle of Judah's speech, a sentence lands that should have broken Joseph's composure on the spot.
"We told my lord, We have an aged father, and a son of his old age, a little one, whose brother is dead, and he only remains of his mother; and his father on that account loveth him" (Genesis 44:20). Targum Pseudo-Jonathan preserves the phrasing exactly. Whose brother is dead. He only remains of his mother.
Judah is speaking of Benjamin, but he is also, unwittingly, speaking to the brother he thinks is dead. Joseph is standing three paces away, alive, listening to his own obituary spoken by the brother who helped sell him.
The words are painful in both directions. For Joseph, they confirm that his brothers never told Jacob the truth. They have been living under the lie of his death for twenty-two years. Rachel had two sons. Now, in Jacob's understanding, only one remains — Benjamin. And that surviving son is loved by his father "on that account" — because he is the last remnant of the beloved wife.
For Judah, the words are a confession dressed as explanation. He is admitting that Benjamin occupies the place Joseph once occupied. He is admitting that the family has been shaped around a single loss for two decades. He is admitting, though he cannot yet name it, that another such loss would kill Jacob.
The sages hear in this verse the entire theology of pikuach nefesh, the preservation of a life. Judah is about to offer his own life because he has finally grasped that one more disappearance will end his father. He learned this lesson, at least in part, because he once caused a disappearance himself.
The dead brother listens, and weeps inside his chest, and says nothing yet.