Hi Diana,
Welcome to the site. Sorry that you had to find us all here and sorry as well to hear what your husband is going through. But you have come to the best place for support and help and you’ll get loads of each from everyone here. I can’t help personally with any experience of CUP as my dad’s diagnosis was of CC. Have you considered getting a 3rd or even a 4th opinion as to surgery? Should you wish to seek further opinions then I know that you will get plenty of good recommendations from people here on the site.
Please keep coming back here and let us know how everything goes. You are not alone in this now and we know how you feel, we are all here for you.
My best wishes to you and your husband,
Gavin