Poor thing. So far so good and you have touched all the bases. I would get vet wrap and gauze, really glob antibiotic salve on the pads and then pad it with gauze before wrapping with vet wrap. You want to keep that nasty wound as clean as possible and keep the antibiotic salve against the wounds. You may have to split the vet wrap into 1 inch strips in order to work between her toes. Change daily. You can soak the foot in warm (not hot) water with some epsom salts in it and gently rub her foot to try to clean off as much dead tissue as possible. There is a lot of damage there but they are pretty resilient little creatures. Definitely keep hitting her with the antibiotics in her water and I'd be giving her some probiotics and vitamins also along with extra protein (protein aids healing)
Also I would put her in a pen where you can keep the bedding clean so she isn't tromping around in dirt and feces like chickens love to do. Roosting is probably painful for her also. Yes, she may very well come out of the ordeal a few toes short of a set but she will adapt. Big goal is to keep infection down and let nature run it's course.
Good luck. Sounds like your friend isn't as knowledgeable about chicken keeping as you are, but at least they yelled help when they needed it. If the infection worsens or looks as though it is spreading, I would consider getting a vet involved.
