How would you manage an elderly patient with a history of stage I CLL and newly diagnosed metastatic ER+/HER2+ breast cancer?

The focus would be on the diagnosis which seems most likely to be life-limiting and/or a source of morbidity. Although there aren't many details here regarding the metastatic ER+ HER2+ breast cancer (e.g. where are the mets? Bone? Liver? Are there symptoms?) one presumes that this is more life-limit...