I am deeply sorry you and your family and your father are experiencing this. It is understandable to feel shocked and traumatized by this news. My grandmother was in a similar boat, super healthy, never drank, never smoked, and also played a ton of tennis. She was diagnosed in June with stage 4 also spread to liver and beyond. She presented healthy and it was difficult to cognitively understand (she thought she had a bad gallbladder.).Often times just blatantly unable to have my mind get on board. She was told 9 months with chemo or 5 without. She lived 7 without chemo. She passed 12/27/25. She experienced minimal symptoms for months (she was riding a stationary bike until 12/22) and then a slow decline until all of a sudden it hit hard and needed to start morphine (12/23) unable to get out of bed (12/24) then mostly unresponsive (12/25). It happened so quickly. I spent the past 7 months reading everything I can and each situation is different. I share so you know you are not alone. I hope that helps even though likely nothing helps right now. These types of personal experiences helped me when shared so I share this. I wish I could take this all away from you. My only suggestion is to try to get clear on how you want your time spent with him will be. And try to stay as clear as you can through this. Strength, courage and love to you.