Has anyone suffered from pleural effusion due to lung cancer like my father?plz help

Dear Friends,
My father is suffering from lung cancer and bilateral pleural fluid effusion,there is a chest tube in his right lung in which pleural fluid gets collected,9 days back he was given first chemo,after which the pleural fluid shot up from 400ml per day to 1100ml to 850 ml to 800ml to 650 ml to 600 ml to 500 ml in consequtive 9 days,I can see a gradual reduction in the pleural fluid,but the day it becomes stable and doesn't decrease I become very worried and depressed....what if suddenly it stops decreasing or shoots up again....
If someone has gone through the same process can you kindly share with me how your post chemo results were like so that I don't get depressed like this everyday,does it take this much time to show results ?....plz help.