FireSprite, if he could contain his narcissism to only when being with her, I wonder, does that mean he is not truly narcissistic? Seems he couldn't control it, if he was. Maybe it's not off-topic either, if it applies to Liz.
Your friend's husband sure was a controlling manipulative emotional abuser though, regardless.
There is a lot of overlap in these personality disorder diagnoses. Narcissistic personality disorder is one of a cluster of "dramatic" disorders where people manipulate others through high dramatics, extreme behaviors, and often a serious lack or complete disregard of boundaries. They all live on a spectrum, but the traits are often similar and a matter of degree or severity. The key to NPD is a person having fantasies of great wealth, success, and beauty (mine was obsessed with wealth and revenge, ugh) and a belief that they are above the law, and entitled to special treatment that they certainly haven't earned. They totally lack boundaries because others are just seen as an extensions of their ego, and people who don't "reflect" what they want to see are cut out or are lashed out at with great force for long periods of time (see an epic, ugly divorce, with one person trying to decimate the other's finances and reputation, or a beloved child who is rejected once they are able to voice opinions different from the NPD -- mine did both).
We've talked about this before, but alcoholism often looks like a lot of other psychiatric disorders. Alcoholics are definitely lower-case-N narcissistic. Also, people are often self-medicating for other issues. The only way to know for sure is that someone dries out for a long period of time (6+ months) and the behaviors are still observed.
NPDs are absolutely toxic. On the outside they're doing just fine inside, it's the people around them that suffer because they have to maintain the facade or risk being emotionally brutalized and mindf*cked for stepping out of line.