Whoa, that lady was way out of line. Now, all the funerals/viewings I've ever been to were open-casket, so it's something to which I'm accustomed. However, not everyone wishes to have an open-casket funeral, and it's certainly not up to anyone
outside of the family to demand that they get to see the body. I agree with lowspark - the proper thing for this lady to do would have been to ask if there would be a viewing or memorial service before the funeral itself. If yes, politely ask for details of the time, date, and place. If no, move it on along, nothing to see here folks (no pun intended, I swear). I know that when I keel over, I wouldn't mind if my family chose to have a viewing for me (unless my body were mangled beyond even the best mortician's repair & cosmetic skill-level), but I would roll over in my grave if someone demanded to Mr. Bottlecaps or any children that we may have someday to see my body without even going the polite route of asking if there would even be a viewing/wake or anything of that nature.
All that said, my condolences on the passing of your friend.