I'm really not good at giving advice at all, but here goes.
My mom had breast cancer 4 years ago. She had surgery, chemo and radiation as well. She had a good chunk of breast tissue removed and she has a nice sized moon shaped scar. She lost all of her hair. Yes - the chemo will make your mom weak. It may or may not make her sick. For my mom it didn't make her sick at all. A little nausous but she didn't get sick. Apparently chemo isn't as bad as it used to be. They put medicine in it to counteract the sickness. Luckly she is just fine now. She goes for her check ups and everything has been fine. She had a lump about 2 years ago but it was just a bit of fluid. Had that drained, not a problem at all.
The thing that got my mom through it just fine was her attitude. She did not see it as a death sentance. She had cancer which has a high survival rate. She looked at it and was determined to beat it. She had such an upbeat attitude. She didn't let it get her down. Sure, she had her moments but over all she was upbeat.
Your mom needs to be the same way. Now, you can't make her change her attitude. Just support her. Hopefully she'll come around and realize that her attitude will go a long way with her treatment.
I hope this helps a little
