thank you sir it is a valuable suggestion from you !!
Your father has been on usually effective drug therapy. I say usually because drug therapy might not be effective against a drug-resistant strain of TB. He should continue with his present medication until he can be evaluated by the doctor(s) who prescribed his meds. A decision on meds can then be made on the basis of how well his disease has responded to this drug regimen.
If the TB bacterium that caused his lung disease has responded well to the treatment, it may be possible to stop the treatment now. In that instance, the TB would be much less likely to occur but follow-up would be most important to detect a recurrence, especially if he should have the misfortune to acquire some other serious disease in the future.
Good luck