Why AF does not go by itself?

Hi Dr.Lam:

I had a friend who quit his job about 5 yrs ago because he was burnt out, tired of work and people etc. He made enough money on stock etc so that he could afford to stay at home. He was traveling, spending time in a cottage, etc. mostly enjoying. After 4 yrs, even a little stress would kick him out of his rut. Later he realized that he has AF and started to work on it. The question: Why Adrenal Fatigue would not go away if untreated?

Thanks