It kind of depends on what sorts of food the person is eating that they feel a need to salt.
Salt is used as a way of enhancing flavor, so one of the tricks that I've used in my cooking is to enhance flavor through the use of foods that have natural sweetness. For example, when making soups, rather than adding salt, you can use fresh vegetable juices that are naturally sweet, mixing them with water, as a base for your soup. Alternatively, you could add a lot of fresh tomatoes to give sweetness. I have a lentil and tomato soup recipe I enjoy that contains no salt. This one is actually best during the summer months though, when the freshest organic tomatoes are available locally, as it is the quality of the tomatoes that really makes the soup. Today, for lunch I am having black beans that were homemade without salt. They were cooked in a pressure cooker in a mixture of 1/2 celery juice, and 1/2 water, with eggplant and celery and spices, and then I added very finely chopped tomatoes, and a little tomato paste, and it is quite delicious!
There are a couple of books that might be helpful to you as far as salt-free cooking goes. The first one I want to recommend is called "The Health Promoting Cookbook" by Goldhamer and Lisle. The recipes in this book are 100% vegan, and contain no added salt, oil, or refined sweeteners. Another book that you may find helpful would be "Eat to Live", by Dr. Joel Fuhrman. The recipes in this book are mostly vegan, and do not contain any salt. Most vegetarian and vegan cookbooks do tend to use salt, so these two really seem to be the exception to the rule. As a vegan who avoids salt, I rely on both of these books very heavily.
Hope this helps, and perhaps if you tell us more about your friends habits I can be of further assistance.