Yosef learns that his grandfather Yitzchok has passed. He has a very emotional reaction. Yitzchok's death reveals his super powers and all of his descendants inherit his qualities.

Sources:

Gemara Megilla 15 A

Parshas Miketz Perek 43 Pessukim 26 - 31

Medrash Rabba Parsha 92 Perek 5

Commentary of Baal naturism on Possuk 31

Gemara Megilla 14 A

Parshas Toldos Perek 26 Possuk 2

Commentary of Rashi

Commentary of B'er Basoddeh on Rashi

Rambam Maacholos Asuros Chapter 5 Halacha 14