What happens when a budding narcissist decides they don't love themselves enough and starts reading books about self love - a train wreck? Lost case?

This is not about nparents. My sister in law has almost all signs of a budding narcissist but is still in college , is there a way to prevent worsening of her behaviour? I found out she checks out self love books nowadays too and don't want to wait if she can be saved. What can be done now?