My grandfather raises a question on Yaakov's assumption that he would lose his share in the next world. After all, he has credit for so many good deeds. He suggests that the loss of even just a small part of his portion in the next world would be tantamount to death, as is the connotation of "mitchayev benafsho" that Chazal speak of.
Yaakov thought that Yosef would not have died if his father were free of sin and, consequently, believed his son's death a sign of his own spiritual demise.
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