John Gill Commentary Genesis 42:32

"we are twelve brethren, sons of our father; one is not, and the youngest is this day with our father in the land of Canaan." — Genesis 42:32 (ASV)

We are twelve brethren, sons of our father
All brethren by the father's side, though not by the mother's, and by one father; they had been twelve, and were so now, though they knew it not, supposing that one was dead, as is next observed: one is not ;
is not alive, but dead; the Targum of Jonathan is, "what is become of one we know not" and the youngest is this day with our father in the land of Canaan ;
see (Genesis 42:13) .