I truly have witnessed a narcissist change some of their behaviors after years of standing ground. It's a very slow and painful process. Doesn't mean it's a happy ending but it does give hope to others enduring the hell. The more one recognizes and stands their ground and gains strength; the better the chances of a healthy outcome. Some narcissists are so damaged internally, they just need love, patience and guidance. But not enabling. (Of course this is not true for all cases).