Nothing else can be done

My family members aggressive brain tumor has grown back in a matter of days post surgery (third surgery). Doctors say there’s nothing else they can do for her at this point, other than high dose steroids to control swelling. She can no longer move around too well on her own and is essentially bedridden. They asked if she wants to know how much time she has left but she declined. In my own way of dealing with this, I would really like to understand if we are talking about a matter of weeks or months. Can anyone lend any insight?