Hello Sir/Mam I just wanted to have your valuable opinion in context to my brother's prolonged nasal congestion/ blockage post Covid , he had tested +ve(post complete vaccination) in the last week Of June 2021, was completely fine by the end of first week of July 2021, post which after about 2 months till date he is continuously witnessing nasal blockage and is unable to breathe completely via nose as a result he is breathing via mouth too specially at the night time,which is also interrupting his sleep.. PFT was done as per advice was satisfactory but still he is not completely okay ,was a smoker since last 15 years ,recently had Quit via 2 months dosage of Champix , now hates smoking seriously..What do u suggest can be the possible reasons for such uneasiness??