My father is feeling like there's a foul smell when he breathes from nose or mouth. He keep getting cough-like sticky substance every 10 minutes in his mouth. His saliva feels weird to him. This is happening since a month now and he's really irritated and disgusted with his state. We've tried medication provided by local doctors but it hasn't helped. There are not many instants where his nose is blocked or he's coughing so it not like regular cough or flu.Not really sure what this is about but he's tired of being in this state. What could it be? And what are the possible measures a to get rid of it? Any medication that will help?