COMMENTARY on 12:59
Mustafa Khattab:

Translation:
When he had provided them with their supplies, he demanded, “Bring me your brother on your father’s side.16 Do you not see that I give full measure and I am the best of hosts?
Commentary:
16   i.e., Benjamin. When Joseph hosted his half-brothers, they told him the number of people in their household for future supplies.

 

A. Yusuf Ali:

Translation:
And when he had furnished them forth with provisions (suitable) for them, he said: "Bring unto me a brother you have, of the same father as yourselves, (but a different mother): seest you not that I pay out full measure, and that I do provide the best hospitality? 1720
Commentary:

1720  Joseph treated his brothers liberally. Perhaps he condescended to enter into conversation with these strangers, and enquired about their family. The ten brothers had come. Had they left a father behind them? What sort of a person was he? Very aged? Well, of course he could not come. Had they any other brothers? Doubtless the ten brothers said nothing about their lost Joseph, or told some lie about him. But perhaps their host's kindly insistence brought Benjamin into the conversation. How old was he? Why had they not brought him? Would they bring him next time? Indeed they must, or they would get no more corn, and he—the great Egyptian Wazir—would not even see them.

 

Muhammad Asad:

Translation:
And when he had provided them with their provisions, he said: "[When you come here next,] bring unto me that brother of yours from your father's side. 59 Do you not see that I have given [you] full measure and have been the best of hosts?
Commentary:
59  Lit., "a brother of yours from your father"-i.e., their half-brother Benjamin, who was Joseph's full brother (their mother having been Rachel, Jacob's favourite wife), whereas the other ten had different mothers. Benjamin, the youngest of Jacob's children, had not accompanied his brothers on their first journey to Egypt, but they had presumably mentioned him in the course of their conversation with Joseph.