A wet cough and cold lasting this long, with mouth breathing and snoring, may suggest a persistent infection, allergy, or enlarged adenoids, which are tissues behind the nose. Since there is no improvement with current medicines, they need proper reassessment rather than continuing the same treatment. Keep her well hydrated, continue gentle nasal care, and avoid exposure to dust or cold air. It would be best to get her evaluated by a paediatrician or ENT specialist for further examination and appropriate treatment.

A cough lasting even after 6 months of tuberculosis treatment needs careful reassessment, as it may be due to incomplete response, drug resistance, or another lung condition. It is important to check if the medicines are being taken regularly and correctly, and whether follow-up tests have been done. Further evaluation, such as repeat sputum tests or imaging, may be required to identify the cause. Consult your doctor to review your treatment and plan the next steps.