This is a request for Reuben to take Joseph with him and to care for him on the journey. AT: "Put me in charge of him" or "Let me take care of him" (See: [[rc://en/ta/man/translate/figs-metaphor]])
The full meaning can be made explicit. AT: "For my wife, Rachel, only had two children. Joseph is dead and Benjamin is the only one left" (See: [[rc://en/ta/man/translate/figs-explicit]])
# on the road in which you go
"while you a traveling to Egypt and back" or "while you are away." Here "road" stands for traveling.
# then you will bring down my gray hair with sorrow to Sheol
To "bring down ... to Sheol" is way of saying they will cause him to die and go to Sheol. He uses the word "down" because it was commonly believed sheol is somewhere underground. AT: "then you will cause me, an old man, to die of sorrow" (See: [[rc://en/ta/man/translate/figs-idiom]])
# my gray hair
This stands for Jacob and emphasizes his old age. AT: "me, an old man" (See: [[rc://en/ta/man/translate/figs-synecdoche]])