A Candida question for a 34 yrs male?

OK Here . MY son who is 34 yrs has Candida for more than a year ,. HE is on a very strict diet ;; JUst veggies and white meat ; he is also followed by a specialist ; but ; he is not feeling better than a year ago . HE tried everything natural ; all the detox who goes against Candida ; and nothing ;;;;; What else he can do Thanks for all the answers NOTE He is doing a doctorate and at the same time he is teaching . IS stress can ba a factor in his disease ? He does not smoke ; drink and MUCH less drug