Hi sorry to hear about your friend, given the right support and providing the cause of the failure is delt with,the kidneys can improve,gastroenteritis in itself is unlikely to be the cause of the failure, more likely to be the long term treatment given for the enteritis,any further help or advice do not hesitate to ring me at anytime on 01449767822.I do hope your friend gets the help she needs and our thoughts are with her! kx.