Heel spurs don't usually cause pain, though there are exceptions. Plantar fasciitis is a different thing than heel spurs and can be hard to treat, though most advocate a stretching and strengthening program for the foot plus icing and rest. If it's chronic, as mine is, eventually you have to do something. There are shoes that can help with this for some people, but they are not normal shoes and can only be bought from stores that specialize in them. Sometimes they help, sometimes not, and sometimes they alter your natural stride so that you get other problems. Orthotics are often used and can go in any shoes. As for the minimum padding theory, that is not a consensus theory. Some believe we all should run barefoot or as close to it. Some believe we need the most supportive shoes available. Mine own view is, if you haven't run barefoot or with shoes that are barely there for many years you've lost the muscle tone to do it without breaking something, but many do swear by it.
Unfortunately, he probably has to stop running. That is a great sport but hard on the body and my suggestion is for him to find an alternative exercise until this completely resolves. good luck to your friend. (Shoes do not solve problems even if they make it more comfortable. Rest and proper care of the condition cure it.)