Cocoa, you can try a search on this site if you want to get some of the past discussions relating to rad treatment. I had 35 sessions over 7 weeks and in general, because the treatments are cumulative, it is very easy in the beginning and gets tougher as time goes on. The worst part is immediately after treatment ends for about 3-4 weeks as rad is the "gift that keeps on giving" as we say here.
Rad is difficult on the throat and I recommend having a feeding tube (we call it a peg) inserted so mom can keep her water and nutrition up as this is very important during treatment. Also it is easier to take meds through the tube.
I was fortunate to be able to continue working throughout my rad/chemo treatments and drove myself to the treatments 60 miles one way, however as you noted, we're all different and some have had a more difficult time.
During rad, different things will happen at different times. Mouth and tongue burning, outside neck skin splitting and oozing, there are different things happening during the treatments. I hope mom is being treated at a cancer center where they have tons of experience. As some of the side effects occur, they will be able to help ease the problems. One thing to watch for is constipation. Try fruit juices (prune through the peg is good) and keep a supply of stool softener handy.
After effects happen differently also. I have very little taste left, my saliva production is way down and I carry a water bottle with me at all times. I have rad burn marks on my neck and scars from the surgery, but not to noticable. Some have had a lot more extensive surgery than I and had plastic surgery to correct some of the scarring.
Hopefully, this will help her get started. Will keep you all in my prayers.