Bill, my condolences to you and your wife. Cancer is horrible, and I am sending healing thoughts in your direction. My husband had cancer some years ago, and some very good advice that we got from others who had gone through it was that I should go with him to his appointments, and take notes. This was so very helpful, as he has no medical background, so even at the best of times (and these appointments were very definitely NOT the best of times) he doesn't always take in every little thing the doctor says, or remember every question he wants to ask. I was there, sitting in the corner with my notebook, not saying anything or getting in the way, but keeping track of all that was said, suggested, prescribed, etc., and then we could go over it again later, clear up misconceptions, get ready our questions for the next time around, and such. I kept a list of all the many different doctors he was seeing (he had 3 separate cancers concurrently, so saw a bunch of docs), kept track of all his medications, dosage, length of time taking that rx, etc. Also kept a running list of his appointments, and, for good measure, the miles of driving to get to some of them, for the taxes. We went regularly to Portland (3 hours), Medford (2 hours), and Eugene (1 hour); it added up.
As to emotional support, just be there for her. Let her howl and rave, and understand that she is howling at the disease, and not at you.
My very best wishes to you both.