Why did Yosef ask whether his father was still alive, seeing as Yehudah had mentioned a number of times that he was?
Seforno: In Yosef's eyes, it was inconceivable that Yaakov had not died of grief over Yosef's disappearance. 1
Beis ha'Levi, Ha'amek Davar: Yosef was admonishing his brothers; "You keep on harping about the danger to your father's life if Binyamin will not return. Why did you not think of that when you sold me?" It was a miracle that he was still alive! 2 Ha'amek Davar - Even if you think that you properly judged me, you should have pardoned me amidst concern for Yaakov, who loved me so much!
Riva: Yosef had asked about "Avichem ha'Zaken" (43:27) i.e. Yitzchak. The brothers did not want to bear bad news, so they mentioned Yaakov, but it is possible that also Yaakov was dead (like Rav answered R. Chiya - Pesachim 4a). 3
Riva citing R. Tam of Orleans: Now Yosef asked if he was healthy. 4 "Chai" can mean healthy - "Basar Chai ba'Se'es" (Vayikra 13:10).
Moshav Zekenim #1: Before, Yosef asked via a translator. Now he asked by himself.
Moshav Zekenim #2: Initially, he did not believe them.
This is difficult to understand however, bearing in mind that Yehudah had mentioned time and time again that Yaakov was alive, and further, Yosef himself had inquired about his wellbeing (See 43:27). (EC)
See Beis ha'Levi.
Riva questions this, for they should have asked about Yaakov first! (Also, they explicitly said "he is alive" (43:28). Rav did not lie, he just said "ask about mother" [and not about father]! - PF)
Moshav Zekenim rejects this without a reason.
Why were Yosef's brothers confused?
Rashi: They were embarrassed at the sudden confrontation with the brother whom they had sold into slavery. 1
Ha'amek Davar citing Chagigah 4b; Beis ha'Levi citing Bereishis Rabah 93:10: Because they had no answer to Yosef's rebuke. 2 All the more so, people will be unable to answer Hashem's rebuke on the day of judgment!
Da'as Zekenim, Hadar Zekenim: They believed that he is Yosef, but could not believe that one who was sold in fetters is now king.
Malbim: They were astounded, and afraid of vengeance. It is as if he said 'is my father still alive, amidst all the afflictions [you caused to him]?!'
QUESTIONS ON RASHI
Rashi writes: "'For they were confounded from before him (mi'Panav)' - due to shame." How else might we have explained?
Gur Aryeh: Perhaps they were confounded out of fear, lest he harm them? The term "mi'Panav" indicates to us that it was out of shame.
