The Pasuk states that "he" told Yosef that his father was ill, but it fails to name the Shali'ach!
Rashi #1 and Rashbam: Whoever it was told him. 1
Rashi #2: The Shali'ach was Efrayim, who would visit his grandfather regularly in order to learn Torah with him. 2
Ha'amek Davar: Yaakov sent a Shali'ach, so it is as if Yaakov told him. He told Yosef to come for an urgent matter.
Rashi and Rashbam: His name is irrelevant. The same applies to the following Pasuk, which states "He informed Yaakov" (48:2).
Da'as Zekenim, Hadar Zekenim: The verse hints to this. If we exchange the Vav for a Pei (according to At-Bash), the letters of the word "va'Yomer" are the same as of Efrayim.
Chazal teach (Bava Metzia 87a) that Yaakov was the first person to experience weakness and illness before his passing. Why specifically Yaakov?
Maharal #1 (Chidushei Agados Vol. 3, p. 51, to Bava Metzia 87a): Until Yaakov's time, each person stood within his own [spiritual] level, without encroaching on another's space. Because of Yaakov's great stature, others were jealous and even pursued him, trying to usurp his place. This brought him to physical injury and weakness.
Maharal #2 (ibid.): Through illness, the physical body fades away, and the person is able to draw close to the Shechinah. 1
Also refer to 47:31:3.2:2. Maharal - The Gemara (ibid.) says that aging began with Avraham for similar reasons; refer to 24:1:1.1:1.
Why did Yosef take his young sons with him when he went to visit his sick father?
Rashi: In order that Yaakov bless them before he would die.
It seems that Yosef was not regularly with his father. (They needed to tell Yosef that Yaakov was sick; and above, Yaakov had called for Yosef (47:29).) What is the reason?
Da'as Zekenim, Hadar Zekenim: Yosef feared lest his father ask how he descended to Egypt; and when he hears, curse the brothers. Rachel died from an unintended curse. All the more so an intended curse would take effect!
Why does the verse say "Shnei Banav," and also their names?
Ohr ha'Chayim #1: This teaches that he wanted them to be blessed along with their father, and also each one individually.
Ohr ha'Chayim #2: They were worthy to be blessed for two reasons - because they are Yosef's sons, and each by himself.
Why does it say "Es" before the name of each son?
Ohr ha'Chayim: Each was important in his own right.
QUESTIONS ON RASHI
Rashi writes: "'He said to Yosef' - One [unidentified] person told him... Some say it was Efrayim, who would frequently learn with Yaakov." What is difficult with the first explanation?
Gur Aryeh: Not many people would travel the distance from Goshen to Egypt proper. We need to explain who it was, and why he would travel there. 1
Gur Aryeh: In the following verse (48:2), however, because many people would come and go at Yaakov's home in Goshen, it could have been anyone who said, "your son Yosef is coming."
Rashi writes: "'He said to Yosef' -... Some say it was Efrayim." But perhaps it was Menasheh?
Gur Aryeh: Efrayim would become more important than Menasheh (48:19-20); it is probable that Yaakov would teach Torah to him.
