New dealing with mom's struggle

Hi,

My 55 year old mom is battling esophageal cancer. On Easter day of this year, she was working (at a hospital luckily) and started to feel faint, several of her nursing co-workers forced her to go to the ER. She was treated by a wonderful doctor that admitted her with the suspicion of a bleeding ulcer due to the stress of the recent deaths of her parents. The next day after an endoscopy was preformed she was diagnosed with esophageal cancer. Later she received a PET Scan placing the cancer at stage 3. She has completed the first stage of treatment, which consisted of three rounds of chemotherapy and 28 radiation treatments.  She had a successful, Ivor Lewis esophagectomy (minimally invasive) in October down at UAB hospital.  My surgeon was wonderful and was able to remove the entire tumor.  

Since that surgery, she has been working hard on recovery. Unfortunately, she has had a few setbacks a mild case of pneumonia and some time without being able to eat.  In early December, the doctors found a large tumor in her brain, around the size of a golf ball.  She had started falling and showing signs of a stroke, with paralysis on one side.  That was removed by a wonderful local surgeon, and will start radiation on monday. She is now recovering from that and hoping to gain back all of the feeling in left my hand, left my leg and recover some of the lost sight on my left eye.  

I, however, paralyzed with fear that the cancer is somewhere else as well. They suspect the tumor was in her brain the whole time, but are unsure because a MRI was never performed only PET scans (which don't show brain tumors). Am I crazy to have hope that she will live more than a few months? I take care of her full-time and I am trying not to lose hope. I know several people here are stage iv and perserving. Does anyone have any advice for proactive changes that have helped in your experience.

Sad and fearful,
Emma1981