Hi Sathome, welcome to the forum.

You don't say whether your sister is going to have surgery or not. If she will have lymph nodes removed from her underarm then I have an idea for you. I had breast cancer surgery and lymph nodes removed 2 years ago so I am speaking from experience. A small heart shaped cushion, around 9inches is perfect, hung on a short ribbon to wear over the shoulder like a handbag. Tucked into the armpit it keeps your arm from applying pressure on the wound under the arm. I made my own really simply, just 2 pieces of fabric - I used fleece, it's nice and soft and doesn't fray - sewn around the edge and filled with toy stuffing. Add a ribbon and it's done. You can buy them but why not make your sister one, I'm sure she would be very touched that you took the trouble. 

Apart from that chemo did give me very dry skin so I'm sure some nice moisturiser would be appreciated too. I recommend Udderly Smooth, not very glamorous but the best by far, at least for me.

I wish your sister all the very best with her treatment. Please do let us know how she gets on.

Kind regards, Mog, x

Hello Moggymad62, I had bilateral mastectomies and lymph removal on left side .We had heart shaped cushions given to us on the breast ward ,they had been made by volunteers and were so comfortable. 
I had front opening nightshirts given to me and nice moisturisers .If she is going to have chemotherapy,you can get her nice chemo hats ,I had really pretty velvet ones from Amazon .As you have to sleep on your back ,a triangular pillow is a good idea too. And books ,to read whilst having treatment ,my kindle goes everywhere with me . 
All the best xx

Thanks Mog for replying and the info. Will look into the cream. Not sure if she’s having her lymph nodes removed, but she is having chemo injections. 

Will keep you posted.

All the best S