Unfortunately, without knowing what type of cancer your grandmother has, it is difficult to say what treatment would be best for her (she would require a biopsy of one of these tumors to try and determine a specific cancer diagnosis).
Even when the type of cancer is known, doctors are notoriously inaccurate in predicting how long individual patients will live, unfortunately. Therefore, I advise all of my cancer patients, and their loved ones, to try and take life one day at a time, and to live each day to its very fullest.
I hope that your grandmother's doctors will be able to offer her some treatment, and that she will remain comfortable.
Sincerely/ Robert A. Wasdcher, MD, FACS
http://doctorwascher.com