Thanks everyone. I have been voicing my opinion on this for a little while but I never seem to get anywhere. The actual owners have never owned a horse before (the 11 year old girls parents) and I know that they would never want to hurt him! However the people that gave him to the girl think they know "everything" and it is rather frustrating.
I am hoping by supplying the girls parents and the barn owner with factual information that they will understand why I am saying the things I am. I do not feel he should have anyone on his back till he starts getting more defined. Plus putting a girl I would call a solid beginner on his back is NOT a safe idea either.