there are some photo recovery softwares that works only to a certain success rate.. if you want complete recovery, better seek a specialised company. even then, it might not guarantee full recovery.
in the first place, i advice all users to purchase cards from reliable brands like sandisk and kingston. kingston has lifetime warranty for most of their cards. some other unknown brands are really killing the market due to its unreliability. your friend totally couldnt take anymore photos halfway which i think is a good thing cos you dont want to continue happily snapping only to find all of them corrupted later.
from my experience, some can view the photos from the camera (thus the photographer is totally oblivious to the fact that they are all already corrupted).. however they cannot be opened on the computers.
some brands are even worse cos the cards are too fat to fit into cardreaders...
for such things, being brand conscious helps..