Hosting A Bridal Shower

My daughter has a friend whose sister is being married. I always thought that the female relations of the bride DID NOT host the shower, but were closely consulted, etc. However, the younger sister (21) and the mother of the bride were not consulted, merely invited and had to quickly rearrange their schedules to accomodate the shower...now the younger sister has been asked to provide the food/refreshments and is looking for guidance...any thots or advice? the wedding is april 4, and the younger sister is the maid of honor and was going to host the bachelorette event...