I am sorry your mum is facing chemo at the age of 82. It’s hard enough without being elderly. I don’t know that there’s much preparation - just be there for her in the days following. After one or two sessions she will know which are her bad days, what she feels like eating etc. and that helps to prepare for the next treatment. Before then it’s hard to know how she will react. Paclitaxel - I found - is not too nasty. It affected my taste buds and gradually made me tired but compared to other chemo drugs it was pretty mild. Dry nasal membranes and bleeding nose every time I blew it, and some muscle aches on day 3,4. Otherwise I was fine - but I am 47 not 82.
Your support and care will help her most of all - best wishes.