Hi welcome to HCM.... Here your friend according to history having plueral effusion like condition.... As he had habit of alcohol drinking liver failure or cirrhosis like chronic liver disease can be present which leads hypoproteinemia and fluid accumulation can occur . Smoking also can lead lung damage by elastase release ... If pleural tapping done than fluid send for cytological examination... Meanwhile his vitals and oxygen saturation should be checked with frequent interval... If needed investigation with serum protein , USG , PT , chest x ray needs to be done Take care Follow the treating pulmonologist advise for further work up