OK, first take a deep breath.
Then, forget the stats.
Finally, learn as much about the treatments as you can.
It is frightening, but this disease IS treatable. Poeple will scare you with stories, but the only story you need to focus on is your mom's. Read the profiles of the people who post here. There are many long term survivors of "inoperable" tumors.
Ask any questions you need to. Chances are pretty good that someone here has good information for you.
Susan