i agree with cutting. i have two plants that were given to me. I was suppose to get one and he was gonna throw the other out cause it was gonna die. way worse shape then what yours is in, nice named her the icu patient. it continued dying a little more till it got used to the pH if that is possible. maybe i just flushed it enough but either way i just cut the dying parts off. Now shes nice pretty, green and almost ready to clone.
good luck with her