Just a point of interest - they told my husband he had lung cancer too. But, after two needle biopsies were done - at two different hospitals - the PET scan was wrong. Nobody knows until they can test it, but it is certainly worth going through the test to find out. Once she knows all of the facts she's the only one who can decide what treatment she will/won't accept. But, you need to be sure she has facts to base her decision on.

Keep your chin up. Your support and knowledge is invaluable to her - especially if she is ready to give up before the fat lady has sung.