Gee, sorry to hear about your brother-inlaw. Please contact me so that I may give you a site to look at on the net. It may just help him a great deal. You can reach me at jlrich9@aol.com Many people who have taken the product on the site have had amazing results. You should check it out. It would be worth a try. As for diet cokes of any kind, I would not even be thinking about such things. He needs to clean up his diet and drink only purified, filtered water. Any type of Sugar or artifical sweeteners are not good at this time of his life. He has poisons in his body that need to be expelled. These toxins and poisons are what is at the root of his problems at this time. Good luck to your brother-inlaw. Bluejay