I wonder if she grips it that way at address, or if it just ends up that way. I know the club tends to end up a little deeper in my right hand after impact than it was at address. Of course, I have many grip/clubface problems!
Anyway, my father, who is 60 and a 4 handicap, has always gripped the club like that; way deep in the webbing between the right hand thumb and index.