Yes, empathy is a real thing. Even if the endgoal of empathy is making people like you, that doesn’t undermine the fact that it exists. But, also, that’s not the endgoal of empathy either. What it sounds like your friend actually meamt is selflessness isn’t a thing. That everything we do always has some sort of personal gain. And that is a lot more of a grey area. I would still say it’s wrong, but you can actually make a good argument that selflessness doesn’t truly exist. Back to empathy, though, empathy is a feeling. Does something good happening to someone make you happy? Does seeing someone be sad make you sad? Do you get angry when someone hurts a loved one? All of those things are empathy. It doesn’t matter whether these feelings are selfless or selfish, they exist either way, and as long as these feelings exist, empathy is indeed a thing.