I've read strong cases be made that empathy can not only be an access point for compassion, love, and treating others properly, but it can also be the access point for cruelty and harm. The Dark Side of Empathy by Fritz Breithaupt goes more into detail; the point being that even when Nick is malevolent and willfully hurts other, it's not necessarily a foreclosure of empathy. He can feel, access, and process the pain he's inflicting, but he's so warped that he derives pleasure from the torment that he can feel in someone else.
Maybe it's the proximity to an extreme state with the safety of knowing he's in control of afflicting it and when it ends. However, you're right, he definitely can empathize with others, but what he does with it is very sick and twisted.
So, there are 2 types of empathy, cognitive and affective.
Cognitive empathy is the
feeling you get when someone tells you about something really good or really bad that happened to them.
Affective empathy is your mental ability to place yourself in someone else's situation and reason out what their life is like.
On one hand of the spectrum you have people really high in affective empathy but low in cognitive empathy. At an extreme, this looks like Williams syndrome. These people trust everyone and are easily taken advantage of.
On the other hand of the spectrum you have high affective empathy but low cognitive empathy. These people can mentally map out what it's like to be another person, but have a hard time feeling it. These are you stereotypical nerds, and at extremes it is autism. Obviously the lowest functioning autists lack either, since they are very disabled, but the average person with what used to be called Aspergers has high affective empathy, but very low cognitive empathy.
Sociopaths have high affective empathy, and no cognitive empathy. This is what enables them to manipulate people with ease.
I think Nick has moderate levels of cognitive and affective empathy. In this regard he's around the norm. This wouldn't be true if he was a sociopath, but doesn't affect whether he's a narcissist or borderline. He also fits some of the criteria for histrionic PD, but I think narcissism explains his personality the best. Specifically grandiose narcissism.
The difference between vulnerable narcissism and grandiose is the degree to which the person needs others to validate their identity. A grandiose narcissist will construct an identity, their brand (lawyer, lawtube pope) and make sure everyone knows it. He wants it so that when you tell someone about him, the first thing you say is "Nick Rekieta is the guy who started lawtube!". Grandiose narcissists don't need constant reassurance around their identity, but if you actively violate/disregard their identity, they will almost always turn to violence (emotional or physical). Vulnerable narcissists need constant validation. They constantly look for confirmation that you believe their identity. I think Nick is a grandiose narcissist because he doesn't actively seek validation, his self confidence is part of his identity, but he will respond in extreme ways if you don't believe his identity. This is why he very obviously hates it when people say he's not a real lawyer, but he also doesn't actively ask people if they think his law advice is useful or good.
The term "covert narcissism" is absolutely retarded and anyone who says it should be hanged. This is a term for Youtube/Reddit psychologists who like to play pretend. They are subhuman, like all Redditors.
It should also be said that it's extremely difficult to diagnose drug addicts. I've seen drug addicts get diagnosed with bipolar and then once they got clean they stopped having manic episodes. Drugs will fuck you up big time. Personality disorders also take 6 months at least to properly diagnose. Within a cluster there's a lot of uncertainty until you can really pull at the threads and see what makes this person tick. I'm not dismissing the possibility that Nick is a sociopath, just that from where I'm standing narcissism better explains his behaviour.