Cocoa,
I too would like to welcome you to this site. You are going to find a wealth of information here as well as support to help your Mom and yourself get through this.
I am speaking from the caregiver's point of view. My husband went through 35 treatments of radiation on this throat. He has a very physical job, so he was not able to work after about 2 1/2 weeks into treatment. He was in a lot of pain, so we learned (the hard way) to keep on top of his pain meds so that the medication would not wear off. If you have to set your alarm clock at night to make sure she keeps up on her meds, do it.
My husband did not have a Peg and he lost over 40 lbs which he did not need to lose. I think because he was a healthy, strong guy, the Doctor's didn't think he would need one. Looking back, I'm not sure that was the right decision or not. But he's healing good now and it's 4 months post treatment. He still has not gained any weight back, but he's getting his strength back and he's eating a lot more now. And after the second month, he was back to work on a full time basis.
Give your Mom a lot of encouragement...she can do this! It's no walk in the park, I won't kid you, but there is light at the end of the tunnel. My best to your Mom, and to you too! Keep us posted, we are all rooting for her recovery.
Take care,
Shelley