This is a very unique arrangement of “Silent Night.” It begins with the the opening phrases of “Clair de Lune” by Debussy, seamlessly flows into “Silent Night,” and melts back again into Debussy. I usually find medleys to be overwrought and inelegant, but not this one. It’s appropriate for many occasions. If you (or if you are a teacher, if your student) have already learned “Claire de Lune,” then learning this arrangement will be fairly simple. The “Claire de Lune” passages are written in the original key and stay very true to the original piece.
I haven’t been able to find this arrangement for purchase outside of the collection “Classical Carols II.” All of the pieces included are standards of the classical piano repertoire paired with a Christmas carol. You can preview all of the pieces at this site. It will give you a clear idea of which pieces are combined and how they fit together. I have played through the other arrangements and enjoy them, though “Silent Night” is definitely my favorite of the bunch.