ACV is not going to cure his problem, it *might* help, but it's not going to cure anything, ACV use with humans and poultry is widely touted as a cure-all remedy, but there is little research to back this up. A LOT more research needs to be done on what it may help or worsen.
If you want to use Apple Cider Vinegar make sure to offer a separate water dish, as he may not drink from the water or as much due to the vinegary taste.
http://blog.chickenwaterer.com/2012/12/dont-use-apple-cider-vinegar-acv-in.html