Steroids may well make her constipated so keep up fluids (she needs to do this anyway to flush it through her system), and try to have plenty of stuff like prunes, dried apricots handy to nibble.
She might feel nauseous/ be sick
I found after a couple of days I felt unbelievably tired, and that is one of the worse things. But that will gradually pass and she will have picked up a bit by her next cycle.
She will be especially vulnerable after roughly seven days, when her WBC count will be at its lowest, - she needs avoid being near anyone with an infection/cough/cold.
Any sign of a temp. contact her cancer unit.
That is very important.
If found I could feel the drugs working down my system, so as cells were killed off I got sore mouth, sore throat, heartburn and then diarrhoea. If she suffers with any of these phone GP and get them to prescribe something, to help.
her sense of taste will change, and coupled with nausea, she may lose her appetite. I found things like jellies, smoothies etc. most palatable.
I wish her the very best of luck. It's tough - there's no point pretending otherwise. But if you listen to your body, and rest when it tells you to, it is doable. And always always tell the chemo unit/her GP about any side effect - so they can give something to relieve them - no need to suffer unnecessarily.
I do need to add that everyone reacts in their own way to chemo - I have given you info. based on my experience, you mum will very likely be on a different kind of chemo, and I know people who have done much better than I did - Hopefully your mum will cope well too 
HTH