I have cancer myself at the moment and I'm currently having chemotherapy. My sense of smell and taste is completely off, and scents that usually smell lovely are making me sick. Unscented shower gels could be good for your mum as well as lotions that don't smell strongly as ive found my skin is really dry.
I need gloves to take anything out of the fridge or freezer and I've found powdered milk easier for making tea since I hurt my fingers taking the milk out the fridge by accident when I wasn't wearing my gloves.
The best thing so far has been a body pillow I bought, and a pillow wedge for keeping my legs raised. It means I can get comfortable in bed. Hot water bottles and blankets are also really nice right now.
I'm not sure if your mum reads, I usually love books but I bought a kindle with a back light as it takes so much energy to turn a light on and off. I got a pouch that straps onto the side of my bed which holds my water, tablets and kindle which is so helpful too. Another thing that has helped is a long handed grabber tool because I found it difficult to bend down and pick anything up if I dropped it, so it could be good to get your mum one of those. I have one upstairs and one downstairs.
A diary is another thing that is good as I find I have so many things to remember but I forget so easy. I keep all the numbers I need in there and keep it by me to write down every single phone call and appointment so I don't forget.
I can imagine how difficult things feel right now, knowing you are there for her will mean so much to your mum x