Hi Fishthejoy,
Welcome to XXXXXXX forum.

Let me know the associated symptoms along with mentioned.
Does your father in law has difficulty in breathing/ chest pain/ cough with sputum/ low grade fever with evening spikes?
Does your father in law has running nose/ sore throat?
Since how long is he suffering from these symptoms?
Does your father has history of weight loss/ loss of appetite/ weakness?

With the available described symptoms and attached prescribed medication details, there appears to high possibility of active Koch's (tubercular disease) chest.
Active Koch's chest is characterized by low grade fever with evening rise of temperature, loss of appetite, weakness, cough with sputum. ESR is raised with sputum may or may not be positive for AFB bacteria.
Kindly attach the image of chest x XXXXXXX if possible.

You should consult with XXXXXXX medicine specialist/ Chest physician/ your treating doctor and should go for thorough check up.
Your father should also go for quantiferon TB gold test for more specification.
Fibrotic lesion in chest x XXXXXXX may be old (if he suffered from K chest in past) or may be new one.
Presence of above defined symptoms with raised ESR suggests the active disease.

Let me know the result of above prescribed investigations.
Meanwhile, he should continue the medicines prescribed by treating doctor.

He should also perform gargles three times in a day; a glass of lukewarm water with a pinch of salt.
Avoid cold drinks, oily food and yogurt and juices.
Take normal health diet as TB bacteria is present in 95% Indians but disease is present in few.
Disease is present in those persons who are immunocompromised, lack of care on health, decreased diet intake.

Hope that helps.
Let me know your other query.
Take care,
Dr. Mayank Bhargava

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