Marty, tell your friend not to go into a panic about what to wear on formal nights. If she wants to purchase a lovely long evening gown that would be wonderful, if not then a lovely cocktail dress, dressy dinner suit, dressy pants with a silky sparkly top will be just fine. Tell her that anything that she thinks would be appropriate to wear to an evening church wedding with a reception at the local country club or fine hotel will be just fine for formal nights.