Her2-positive breast cancer

Hi, 

my mum was diagnosed with her2-positive breast cancer 2years ago now, she has had a mastectomy and is 18 months in to her treatment. She is struggling mentally and anything we try to do to help and support her, is the wrong thing.. we as a family are desperate to do the right thing by her.. please does any one have any suggestions or something that's helped you or a loved one?

Thanks