My Step-Father was recently told he had Lung Cancer. Waiting on test results to find out what type. Drs. recently told my Mom he is in stage 4. My question is-What exactly is stage 4? And – How much longer does he have because Drs. don’t believe it can be cured due to the severeness of it? He is in his 70’s. Any info will be appreciated. Also, if you have a smart comment on this don’t bother- this is a very touchy situation for me. Thanks.