To me there are just some things that you may not need magic for and this is one of them. Albeit, this is my just my opinion, and nothing more.
You may want to try at least cutting back on your sugar intake at first. I wouldn't really suggest quitting cold turkey as this will more than likely not work. Let's face it, if it were that easy for you, you would have done that by now, right? If you seriously are concerned about not ending up a diabetic,though. This may help you. Keep a journal, get those check boxes up and keep a list of how much sugar you are taking in, slowly, week by week, cut down on the artificial sugars. Try replacing those sugars with natural sugars like fruits. From my own personal experience, you can get so far away from the artificial sugars until the sweetness of an apple is enough to sate your sweet tooth.
There are countless sources and recipes online for fruit smoothies. If you want to write your own mantra and chant it in between slurps then, there you go, some mysticism added. Your brother can try the same with caffeine, meaning cutting back at first. In any case, my personal suggestion is not total depravity, but moderation, and taking your time. Unless of course your in immediate danger of becoming a diabetic, in which case cold turkey will at least give your system a break from the abuse, and you would still probably need to replace those sugars with more healthy ones because the craving is still going to be there. Other than that, wean yourself off. I hope these pointers help you in some way. I'm not a health care provider, so you would do well to research some methods yourself. Nevertheless, I believe that this is a decent, practical starting point, that will aid in you attaining positive long term results. Light and Love.