I had a query for my father. For the past few months or so, he is coughing up hard balls/chunks of opaque greyish white phelgm after waking up in the morning. It is extremely thick and usually the thickest in the morning. Sometimes it also contains a yellowish tinge. For the rest of the day he has a sticky phelgm but not like the one in the morning. He always expels phelgm whenever he coughs. The phelgm also contains black particles, even though he is a non smoker. No fever as such, non diabetic. Only on thyroid medication. Tried antibiotics but did not help. Please suggest medications.