My experience was that the initial side effects were much more mild than I was braced for. However, they did get worse with each cycle such that 5 & 6 were pretty rough. I believe the effect is cumulative. However if your mum has had limited side effects so far I think that is a good sign.

The most shocking side effect for me was the pain caused by Filgrastim injections on day 8/9 of the cycle, it was mostly manageable but on the 4th cycle the pain was intense in my lower back and hips.

I was on Pola R CHP. Best wishes to your mum

Everyone is different. What goes in is going to come out in someway. I found disposable underwear was most helpful. I vowed to walk at least a few steps everyday and pushed further each day. I ate a few bites many times a day I did not want full meals. I used protein shakes many days when I had trouble with taste and appetite. There Zofran for nausea took care of that. Getting outside for me was a lift. I did not have pain. Realizing it is a treatment and the side effects can be managed. One day the treatments will end.

I had some nausea and tiredness right für the first cycle for a couple of days. I would recommend to take the anti nausea medication right away at first signs of it. I did not and taking it later made it less effective. Lesson learned. After that I felt good.
However, I developed a rash after BR treatment 12 days later after my first treatment and some night sweats. They suspected that one of the pre meds was responsible for the rash. I stopped taking the medication right away. I was put on a Prednisone course which ended 3 days before my next appointment. No rash at that time. The next cycle with chemo brought the rash on the same evening. They don’t know if the flair up was from the pre med or stopping the Pred too early, the chemo…I took additional Benadryl on that first evening and the rash receded quite well before my next day appointment. I noticed 5 minutes after I received Dexamethasone as a pre- med ( had it as well the day before) that the rash intensified. That was before the chemo and immun therapy was started. Rash got better after one night without med intervention. Now they are trying to figure out what triggered the rash.
Hope that your mom will stay symptom free. I think most patients will remain symptom free! Best wishes to you and your family.