What Is The Treatment For Severe Asthma?

Hi my dad had tuberculosis infection 2years ago, he had treatment and also had an operation, removed the infected left lung part, now he is having severe breathing problem Severe asthma (when he walks his breath seem to get low and he breaths very fast and loudly), he had been taking bronchitis sprays, medications for the infection, anti bacterial etc medicine for months, he recently had a test which says in summary "minimal bronbhiectasis also noted in the medial segment of the left lower lobe. Focal linear scarring is noted in the apicoposterior segment of the right upper lobe. There is evidence of thickening and associated marked luminal narrowing of the left main bronchus, the wall thickness at the size measures 0.5cm. Findings could be secondary to previous tuberculosis infection n stricture formation, there is presence of sub centimeter lumph node in the lateral aortic region measuring 0.5cm.

My dad is diabetic and he is 80+ years old, doctors has told him that he cannot have the surgery to have a replacement/transplant of the thickened bronchus because of his age, diabetic and also this surgery is not possible in the country he is living..

Can you please guide me where to take my dad for surgery (i mean which country has the best medical facilities and treatment), what country? how much it will cost etc