They volunteered the family arithmetic before he asked for it. Targum Pseudo-Jonathan on Genesis 42:13 preserves their confession: twelve brothers, one youngest still with the father, "and one went from us, and we know not what hath been in his end."
The sentence that says everything
That second clause is the key. The Aramaic — "we know not what hath been in his end" — is the brothers' cleaned-up version of what they did to Joseph at Dothan (Genesis 37:24-28). They threw him in a pit. They sat down to eat. They sold him to Midianite merchants. They told their father a lie involving goat blood and a torn coat (Genesis 37:31-32). And now, standing before an Egyptian official who is asking about their family, they compress all of it into a passive phrase: one went from us, and we don't know his end. The Aramaic paraphrase, which reached its final form in the Land of Israel around the seventh or eighth century CE, preserves their evasion word for word.
Joseph hears his own story told at a distance
Imagine standing there. You are Joseph. Ten men who sold you into slavery are now, in your presence, describing your disappearance as something that simply happened. No acknowledgment of agency. No naming of what they did. Just a vague "and one went from us." The rabbinic tradition reads the brothers' phrasing as the exact moment Joseph realizes they have not yet repented — they are still editing the story.
The takeaway
Evasion is a kind of confession. The brothers reveal their guilt in the very softening of their language, and Joseph hears every missing word.