Question about cancer and tumors?

My cousin in his 30's has malignant tumors in his kidney, pancreas, and 2 in his brain. I'm not sure which tissue the cancerous cells came from first. Now I know pancreatic cancer has a very high mortality rate, but is that only if the cells are from the pancreas. Is it not as bad if its like liver cancer but metastasized to the pancreas and brain? Also one of the tumors in his brain cant be removed, so there going to try and radiate it out. Will that make it go away? Just trying to understand this...