Thanks for your question on Health Care Magic.
I can understand your mother's situation and problem.
In my opinion, we should first rule out MDR (multi drug resistant) tuberculosis in her case.
She has already taken treatment for two times.
Now she is having tuberculosis third time and even after starting treatment she is not improving and having continuous coughing.
All these favour possibility of MDR tb more.
So better to first get done sputum AFB (acid fast bacilli-
bacteria causing tuberculosis) culture and sensitivity report and rule out
MDR tuberculosis.
At present give her centrally acting (acting on brain cough centers) cough suppressant like
codeine, levocloperastine, Benz pearls etc.
All these are prescribed medicines, so you need doctor 's prescription for them.
So consult your doctor and discuss all these.
Hope I have solved your query.
I will be happy to help you further.
Wishing good health to your mother. Thanks.