Angelika, I am a survivor of pancreatic cancer, and I certainly know how difficult this whole cancer thing can be. I see, from the other side of the fence, how people struggle to talk to me, and I'm sure that they're feeling what you feel, about not knowing what to say.
Sometimes others will admit to me that they don't know what to say, and I tell that that it really doesn't matter. as long as they're there and talking.
Have you ever considered asking your husband what he'd like to talk about? He may have very specific worries, but not want to burden you. That may not work, but it also might get a meaningful conversation going.
My thoughts are with you and your husband, and if you ever want to talk, I'm here.