On average, how long will a cancer patient with tuberculosis have after being put on narcotics?

Hard to answer: Based on info. U gave. Pain medicine is usually prescribed for terminal cancer, but doesn't necessarily correlate well with remaining life expectancy. If the oncologist is recommending "hospice care", that usually means less than 6 months to live. Each person is different however, so this is not necessarily 100% reliable. The main thing now is to treat pain to make the patient comfortable.