Is it possible that a man can lose 9 kilos in 1 month time? he still eats and drinks but inspite of his cancer which is not terminal yet

Weight Loss: A 20-pound weight loss. In the setting of cancer, despite "adequate food and drink intake, suggests a cancer cachexia syndrome, which may indicate the cancer is elaborating a "wasting" hormone known as tgf-alpha. It is best to consult with his oncologist and get to the bottom of this.

Get re-evaluated: This is unusual if truly not terminal. Rapid weight loss could be from fluid loss (dehydration). I would suggest notifying your oncologist (is the cancer unexpectedly growing / spreading faster then before?). Side effects to other medications or treatments? New disorder developing (such as thyroid problems?). Many more possibilities that only your doctor(s) can begin to investigate.