Mom with brain, liver, bone mets

My mom had both breasts removed 4 years ago. This past December she had been diagnosed with mets to the bone and liver. She has been going through chemotherapy, and so far it seems to be working.
However just this past week brain mets were discovered. My mom is only 52 years old. She is not sure what direction to go in. The doctor has said we can treat it aggressively or we can call in hospice. My mom is really scared, as we all are, and although she is a fighter, she is having a hard time making up her mind.
She does not want to go through with all the treatment if it is only likely to give her less than 6 month extension. Everything I have read on the internet seems to point to there being little hope.
My question is, are there any success stories of long term breast cancer survivors with brain mets?
Any advice would be greatly appreciated.
Thank you