8mm groundglass nodule

Hello I am new to this site. My husband went to the ER for an unrelated cause and the ER docs found on a CT scan an "8mm groundglass nodule within the right upper lobe. There is also mild dependent subsegmental atelecrasis bilaterally." I'm not sure what that second sentence means or its signficance. He is only 40 years old, but has been a moderate smoker on and off for about 15 years. We saw our Inernist at the local teaching hospital and she ordered a follow-up CT scan in 2 months. I am terrified as my mother died of non-Hodgkins lymphoma at the age of 42 in the 1980s and the ER staff was very frightening about it, although our regular Intenist was much more calm. Any stories or words of advice are appreciated.