My friend around 70, has tuberculosis and lung cancer. about to be go on narcotics. how long will he have?

Weeks - months: Not long if the reason he is being put on narcotics is because there is nothing else to do for him or treat him with.

Unusual these days: Tb has been well controlled for a long time except unusual circumstances of immunosupression etc. Lung cancer is common in smokers and well treated if found early. If late stage already, survival is limited t o 2-3 years generally even with treatment. If hospice stage that us advanced and even more limited.