Diet Gerson cancer diet?? Anyone tried

My brother-in-law tried the very extreme healthy diet instead of treatment for prostate cancer about 4 years ago, vegan, coffee enemas, no alcohol etc prob even tried rubbing kale on it ( just read the Mountain Lion post) and he is now having chemo for the cancer that has spread through his body and has not got a very good long term prognosis.  My GP has told me the same advice as ladies have suggested above - healthy weight, calorie control/smaller meals, lots of veggies, no sugar restrict alcohol to a minimum, diet or supplement rich in antioxidants and all this is together with my treatment and almost as important as good diet is exercise, think every specialist I have seen so far has said how important exercise is. Good luck