My cousin is an actor. How can he act like a sociopath?

So he asked me and i have nothing… Can anyone please tell me how to act like one i don't want to look like an idiot so please answer quick… Alright he asked me how they talk, there body language and sarcasm… And when they show feeling are they exagerated… He dosnt have a major role so hes bascially just ganna say 5 lines… Any ideas… Sory about grammer i'm using my iphone and keep clicking the wrong things.

Added (1). Lol there's a reason he only has; like 5 lines in it.

Search up "The Joker Disease" and has he seen the Dark Knight? Because the Joker is basically that.

If he's an actor he should know how to play any character.

But sociopaths don't appear outwardly any different to anyone else.
That's why they're so dangerous.

Sociopaths have no remorse, or conscience, they feel entitled to do anti social acts, and are oblivious, towards other peoples, or animals pain or anguish---they also have an inflated ego, to over compensate for their low self esteem---they are also pathological liars---I would suggest watching Faux News, for their body language, and the Koch Bothers, and any serial killers articles or videos--they go from a blank expression, mocking, to exaggerated body language--Good Luck