questin about collapsed lung

hi, my father is now 60, his lung collapsed when he was 18, he's been healthy all his life, then 4 years ago the area where the lung used to be started to leak a fluid and he got very sick, he was in hospital and no doctors seemed to know what to do for it, apparently it is very rare. Anyway we managed to cure it by taking drastic measures and a very very strict alternative health diet etc..
now 4 years later the fluid is back, its not continuous but every few hurs starts to gush with liquid. Once again no doctors seem to understand why?
if there is any doctor out there that has more information i would really appreciate that!
(this question is put under lung cancer, but he hasnt got cancer i just couldnt find any other forums for the lungs!)