Hi there hunny ... bless ya .. ive been on both sides of cancer and l found seeing others having treatment , for me is far harder ...maybe (with mums consent ) a call to her oncology team to ask those questions .. tell them you feel confused by it all .. they must get lots of us doing that ... my daughter in law came with me and wrote everything down ... coz as soon as l heard the word cancer my brain shut down ... so glad she was there ... so have paper and pen ready .. and don't be afraid to ask them to repeat things 

I'm a breast cancer lady too ... and now 7 months post op ... and it's not half as bad as I was expecting .. and here l am writhing to you ... so try to not over worry .. you can walk this path holding each other up .. while holding her hand ... and tell her from me, she can kick cancer bum all the way down the road ... it's got loads of ups and downs but you can do this TO GETHER. . Big hug brave lass ...