Clean, peel, and boil taro until fork tender. Then cut into 1/2-inch cubes. Wash luau leaves thoroughly, and remove stems and fibrous parts of veins. Place washed luau leaves in large saucepan and add water. Bring to a boil, lower heat, and simmer for 1 hour, stirring frequently. Drain luau leaves thoroughly, stir in coconut milk, and sugar and bring to a simmer. Add diced taro and cook until heated through.