Unfortunately lost an employee this way about 18 years ago - just about 12 months from diagnosis to the end. Have a relative who is a physician, she told me at the time that if the recommended course of treatment was just chemo and not surgery, the prognosis was grim - she was right.
That said, there are continuing advances in treatments, and your friend and his doctors haven't given up yet since he is getting chemo, so there's some hope.
Good luck, tough situation for all.