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]])
"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]])