My future MIL wants to wear pants to the wedding instead of a dress. She sent a message to my mother through my FH asking if my mother would wear pants too. I know my mom doesn't want to wear pants and I know I don't want either one of them wearing pants. Granted, our wedding is not super formal, but I want our mothers wearing dresses, its tradition. I know that my FMIL has a lot of health problems and is aftraid she wouldn't be comfortable in a long dress. She is the matriarch of the family and is used to everyone listening to her when she makes a "request." I feel like this is my wedding and I would be able to deny these "requests" but I don't want her or my FH getting upset with me. Any suggestions on how to handle this??