My FMIL recently asked my FH if she could dress her granddaugher like we are dressing our flower girls. Her granddaughter was not asked to be a flower girl because she is unpredictable, doesn't listen, and is best described as a holy terror. However, it is my FH's niece so my FMIL thinks that she should automatically be flower girl. How do I tell her that it's completely inappropriate for her to dress her granddaughter as a flower girl?