Lung Cancer in Non-smoking Women ...

Nov 2005 my mom was diagnosed with Bronchioalveolar (BAC), and had her left upper lobe removed. What was crazy about this is my Mom is a non-smoker. After asking questions and reading about this cancer we learned that this strain of cancer is in non-smoking women, and makes up a small percent of lung cancers.
Shortly after surgery she did chemo, it made her very ill. Every side effect possible, she had. When chemo was done, she began to heal, get stronger, and back to the way she was before in just under a year.
The next 3 yrs she did CAT scans, lab work, and saw her oncologist. She was more health aware, than before. She was living & eating right, and the CAT scans were showing cancer free; until this Feb 2009, 3 yrs from first diagnoses. A shadow appeared, and the doc wanted more test, x-rays, and scans.
Mar 16 she had surgery, the plan was to remove the upper right lobe. But that didn't work out, all they were able to remove was a few tumors to test. The test confirmed what the doctors thought, the cancer had returned.
The doctors say the chemo will not cure it, they hope it will shirk the tumors, and prevent new ones. Her oncologist wanted to wait for her to heal from surgery before starting any chemo. Three weeks ago the surgon released her, and chemo was in motion to start.
Until 2 wks ago, May 16th. She couldnt breath, and admitted in the hospital. Over night at first, but she got worse, fast. She was on oxygen set to 3-4, next day set to 5, and that night 7-8.
After a few xrays & scans they determined she had fuild around her lungs. First they drained over 2 litters of fluid. After testing the fluid, it came back as cancer as well. Over the next 48hrs over 8 litters of fuild was drained, and a chest drainage tube put in.
Her cancer has become very aggressive, moving rapidly through her body. in a matter of 3 days it had tripled in growth.
Now it is out of the lungs, moving into her body, going up in her shoulder & neck ... it is just time that it reached her brain. Doctors told her she is terminal, the cancer is in the final stage. There is nothing medically that can be done, just keep her comfortable and control her pain.
All she does is sleep, we are lucky if we get her to take a few sipps of water, or a bite of pudding. She seems confused and sometime does not under stand what is being said to her.

I just would like to know, how long is the Final stage? because just watching my mom go from a healthy active women to where she is now, who can not even hold a cup to drink from in little over a 8 days, it is crushing me.
~ thank you ~ Deb