I have 3 cats that are coughing( like they have a hairball), sneezing and 1 has some green mucus when he sneezed recently that I don't know what to do with. My One male cat has gone through it and he is getting better, no more sneezing & coughing but the other 2 are still couching and sneezing and getting hairballs too (ALOT). I have changed the food to hairball treatment and that has made it better so far. Can you help me to figure out what I should do??