Mum diagnosed with triple negative breast cancer stage 4

Hi there, 

My mum has been diagnosed with triple negative breast cancer, stage 4 which has mestasized to her liver. Our heads are spinning, that she's gone straight to stage 4 with no previous cancer. They are going straight to chemo in a few weeks, but mum has basically been given two choices, to take part in a clinical study or standard chemo path. We're all so confused as which route to take as we were expecting a clear treatment path rather than options. Does anyone have any experience or advice, even words of reassurance that I can pass on to her. She's 72 and doesn't feel strong enough to manage the more agressive clinics study, but clearly is confused which path to take. Thanks Jo x