My mum has recently been diagnosed with secondary breast cancer - it’s returned in her lungs less than one year after treatment. She hadn’t yet started chemotherapy. On Tuesday she was admitted to hospital having developed fluid on the lung which the Drs say “is caused by cancer”. She has had various treatments in hospital since Tuesday the latest being a procedure to seal the space between the lung & the pleura. 
I know very little about this condition & worry about what this may mean for my 76yr old mum. Has anyone had any experience of this? Any info, advice etc would be appreciated.

thank you