Dear Nancy, I am crying reading your post. This must be so hard on you, dear girl...
My father in law had lung cancer and had radiation and chemo same time plus he had half of his lung removed. They do tests on your mother to check if any new lesions appear on bones, liver, brain, etc. And they also checking how the present once shrink and how fast. this is very important because if the tumors don't shrink they have to adjust her medication. This all is good, it means she is in good hands now as a mother I can tell you she prays that you and dad don't get very upset or at least not to show her that.
Sweetie, I have plenty health issues and now i was also Dx with 2cm mass on my lung. I came home yesterday and still did not tell my kids especially my daughter: they love me so much and worry too much. My heart bleeds thinking how upsetting these news will be to them and hesitate to talk about it.
No physical pain can be compared to the pain which mother feels when her kids worry sick about her.
Stay strong; i know this is easy to say than do, but try to do it for her.
Best wishes, Moldova