Sforno on Genesis 42:13/ספורנו על בראשית מ״ב:י״ג

1שנים עשר עבדיך אחים, בני איש אחד בארץ כנען, what we have said before can easily be proven. After all, our father is still alive in the land of Canaan. Both he and his neighbours will confirm what we have told you, i.e. that we used to be twelve brothers, that one went missing, and that the youngest remained to look after the affairs of our father’s household. You can confirm that we have spoken the truth by checking out all these details.