My mother had whole brain radiation 1and 1/2 years memory getting worse how will she die from this? She has breast cancer that was diagnosed stage 4 3 years ago I live with her and her memory in last few weeks has gotten worse I'm assuming the cancer has grow in brain again ... I'm trying to prepare myself to what will happen how she will die from the metastasis to the brain she is still in chemo and the cancer is under control everywhere else.