Firstly, sorry to hear about your freind and secondly Great report. I'm sure what you saw and experienced was in full alignment with the peace of mind around your freind you were after.
The way i see it, Death does not exist. Of course all physical things are impermeant, but the animating force and energy ( & soul) behind it all is eternal. Death is just another threshold for the soul to pass as it continues along it's journeys, in which ever shape or form follows, be it reincarnation, or reabsortion back in to that ocean as it makes it's way back to the mountain top to flow down to the ocean again.
I also felt i once visited the place before death and birth during a similar journey ,although it was much more mental than visual. Strange place indeed yet stranger more is the sense of familiarity it has.