First, your friend should purchase a book titled "The Southern Gardener's Book of Lists" by Lois T. Chaplin. Therein will be found lists of annuals/perennials/shrubs/trees that will grow in this adverse situation. Wind is the enemy. To be successful one must figure out ways to foil the wind using fences, stone walls or shrub rows of Wax myrtle and/or other shrubs which are listed in the book. Based on my years of landscaping in this type of situation it is important to amend the soil with compost and manures at the soil surface annually. Also, one must be content to start with small, young plants which will adjust to the winds in time. During periods of high wind your friend should walk slowly around the property 'feeling' the wind trying to find quiet spots. These spots are very often found tight to a building or on the leeward side and can be utilized for growing roses and other blooming shrubs. It is possible to have a salt build-up in the sandy soil. Scant handfuls of gypsum worked throughout the garden beds every few years would probably be a good idea.