Don't worry, death is nothing to fear. Hopefully your grandpa had a good, long life. I am not a doctor but I saw my dad and sister die from stomach cancer and pancreatic cancer at the age of 48 and 52. Now my mom is 80 and dying from pancreatic cancer. Ask the doctor all your questions but be aware that you will get some pretty gross answers. I don't know why he would be throwing up so much, maybe from the medication. If he is being fed by a tube and throwing up, personally, I would stop the tube food. The goal is to make his passing as painless as possible; not to keep him alive while being tortured by cancer. My sister was totally drugged up and mostly sleeping. Remember to only think of your grandfather right now, not the pain you will feel when he passes. You will see him again when you pass away. Your grandfather wants to be in peace not pain. I am sending you strength and a hug (can't find my emojis).