Stage 4 lung cancer, given 12 months 18 months ago, lost heaps of weight, now large mass in kidneys, need to know how long left to take kids 4 l visit?

Cancer prognosis: Sorry to hear about the grim diagnosis. It's impossible to tell exactly high much longer without knowing the functional status of the person. 6 months is generic survival span in most cases, but it can be more or less than that depending on the aggressiveness of the cancer, etc.

Not much longer: It is always difficult (nearly impossible) to predict the inevitable: you should go now and spend as much time together as possible (for as long as possible).