Like they treat everyone- badly. The selfishness is always there, even with aging parents. They make demands on them- money, things, an ear to listen to their woes (which increase as the narc ages, life catches up with them)- basically the full narc package. with no concession to the age of the parents. It is one of the many reasons I have no time for narcs. They are unpleasant people, self-obsessed and simply not nice to be around. So I am on a campaign to educate everyone about narcissism, and the dangers thereof. My little answers can only provide a snapshot, in relation to a tiny aspect of narcissism, and it is a big subject, so you need to study it to understand it properly. This will pay enormous dividends. You will be able to better deal with any narcs you are stuck with, like relatives, and will be able to see what is going to happen if you have the misfortune to be in a relationship with one, so I am recommending everyone learns about it by reading. Everyone normal should become an expert on narcissism. This is surprisingly easy, because they always act the same, all the time, and they do the same things to people over and over again. There is a narc pattern. So one good book will do it. The best book I ever found on narcissism generally is Prepare to be Tortured- the price you will pay for dating a narcissist. AB Jamieson, Amazon.