Don't kno what to say....

My friend at work just got diagnosed with pancreatic cancer. He was being treated for back pain and all of a sudden he is diagnosed with cancer. I don't know what to say to him without making him feel horrible. I don't know the details. I've worked with him for 6 years plus he is related to my sisters husband. I heard pancreatic cancer is the worst kind you can have. What do I say?