I can only speak from my own experience. I agree that to do chemo or not is a very frequent question on this site. In fact, I think it was the first question I asked when I got on this site when I was first diagnosed.
I had Whipple surgery since my CC was outside the liver in the bile duct near my pancreas. They got all of the cancer and the pathology showed that I had no lymph node involvement. My Oncologist said that if there had been lymph node involvement he would strongly suggest chemo, but because there was none, he left the decision up to me (but he leaned toward doing it). Like others, I was not very keen about doing chemo, but the doctor said that the type I would get (Gemzar) is "well tolerated". He also made the point that if I didn't do it and this aggressive cancer returned, I may have regrets.
I opted to do chemo for 6 months and while it was no picnic, I was able to get through it and have not regretted doing it.
To chemo or not is such a personal decision and as Lainy said there are a lot of things to take into consideration (age, stage, health). No one can tell you whether it will help or not, so it's mostly a crap shoot.
I wish you and your mother the best and let us know how things are going.