I'm definitely a believer that changing your diet can help you get well again. I eliminated grains and sugar for a period of time and got better. It was hard to do at the beginning, but when I started feeling so much better, it wasn't a sacrifice for me any more. For me, there was definitely a fungus link. I had to starve the fungus. And a big YES, that environment can play a factor in your health. Mold can cause serious problems. If your friend does believe there is a fungal etiology to his problems, (whether via the food or environment)there is only one way to find out....experiment with an antifungal program which includes eliminating the fungus feeding and fungus containing foods. Cheers........
Kim