Cas,
I'm sorry you and your friend are having to face this, but you'll find a great deal of support and helpful information on this site.
I can't add a whole lot to what's been listed above, but I would emphasize that the effects of radiation can sneak up on you. When I was going through it, I was warned about many of the unpleasant aspects to watch for, and when I got through the first 2-3 weeks feeling pretty well I thought the whole thing was overblown. It was shortly after that that I felt like I hit a wall with the burning sensation in my mouth, severe dry mouth problems, and tendency to develop infections. So you may notice some sudden changes in your friend's responses depending on how her system reacts to the treatment.
Is she being treated at a major cancer center?
Cathy