Oedema On Face, Abdomen, Legs. Chest Tightness. Has Tumors On L5 And C7, Brain Tumor. Life Expectancy?

hai there, my mum had breast cancer 17 years ago.she had mastectomy and radiation . she was on tamoxifin for 5 years.she was fine after that for all these years.last October she had complaints of nausea,lack of appetite and abnormal walking gait.scan reveals a brain tumour 4cm on cerebellum .she also got tumours on L5 and c7. There is a lesion on the lung as well.she refused to have any surgery ,radiation or chemo. oncologist is giving her steroids i think.Still not 100% sure wether is metastatic breast cancer or another origin.she is 69.now she got oedema on face ,abdomen and legs .i am not sure it is ascitis because she is cared at home now.she also complaints tightness of chest.she cant walk now and very sleepy all the time.does all these indicate end stage?how long she will live in your experience?