I am not a long arm quilt, but I would venture to say that this is not doable as she wants it. Yes, use your recovery from surgery to put this off and tell her to consult another long arm quilter. A fellow guild member does make two sided quilts that are amazing. Her secret is: do as you go quilting, block by block, and she does this on her domestic sewing. Pretty sure your friend could do this, but it would entail much use of her seam ripper. And the use of some online tutorials. Hope your recovery goes well.