Hand, Hand, Fingers, Thumb by Al Perkins has been a top favorite for all five of my kids.
Another favorite at that age is Ten Little Fingers and Ten Little Toes by Mem Fox (I think) and Helen Oxenbury. But the illustrations are a great part of the story, so it depends how well your friend is able to show the pictures. And it's kind of interactive, too. A LOVELY book, though!