I just tried it. "you treat the victim's wounds and call for help." still gives you the "all is lost...." answer if you go back to the mayor.
Edit : Damn i just tried using medicine and the victim was removed successfully, but it still bugged out on me. I managed to finish this quest on my 2nd playthrough(partly, it was still buggy, see bug list thread) but now it seems i cant get it to work on my 3rd playthrough.