I'm really worried about my dad. He's been having this thick, yellow, milky mucus with a little bit of blood in it from his nose in the mornings. The rest of the day, there's no blood, just yellow-green mucus, even though it's been two weeks since he started antibiotics. He was prescribed Azithromycin for five days and Doxycycline twice daily. Twice he coughed up some blood, but it stopped on the same day. Now, he's mostly coughing up white, thick phlegm. This started after his fever went away. What do you think might be going on? Any advice would be greatly appreciated.

do chest xray