I deal with many clients who have this problem and when it occurs within your family, this article provides good advice on how to deal with it.
There are a few signs of narcissistic behavior that parents should watch out for:
Inflated ego: The narcissist has a huge ego. Narcissistic adult children demand that you do what they want, try to control you, and push every boundary. Every time you give them what they want, they demand something else. They say your job is to make them happy.
Need for validation: A narcissist needs constant admiration. Often, they need praise for simple tasks, like making an appearance at your birthday party. You may find yourself giving your narcissistic adult child an inordinate amount of praise over something that’s a normal and expected part of family life.
A sense of entitlement: The narcissist feels entitled to things they should have to work for. For example, they may demand ridiculous things like financial support well into adulthood. Or, tasks they should be doing themselves, but you find yourself performing…such as doing their laundry and folding their clothes, filling out their job applications, calling into work sick for them, or fixing their breakfast or lunch to take to work.
Exploitation: A narcissist acts without conscience, thinking only of themselves. They lie, trick and steal to get what they want. This exploitation can be glaringly obvious or very subtle, so be on the lookout if you feel used. This may manifest as their throwing temper tantrums, blackmailing you by withholding their love or your grandchildren, trying to entice you with sweetness and affection when they want something, and blaming their behavior on you.
Distorted thinking: A narcissist occupies a fantastical world where he or she is the greatest and most important person in the universe. In order to maintain the fantasy, narcissists lie. They often deny things that are obvious. They may make up fantastical tales to support the fantasy.
Unpleasant personality: Contempt and belittlement are the narcissists’ tools of choice. When they feel threatened by success, they get mean. Watch out for those who are constantly putting down other peoples’ accomplishments. You may find your narcissistic adult child talking badly about their friends behind their backs, but pretending to care for them when these same friends come around
Read more here: