These people are not worth talking with, to be honest, I suggest moving on. There are tons of people with these kinds of insane unjustified beliefs throughout the world. This person is probably ~15 and it's very possible they have not fully developed empathy yet. Some people don't develop empathy until they're well into their 20s. Some do younger as well, but its not consistent.
Their entire worldview exists to make them feel special, and unless you have a close personal relationship with them it's highly unlikely you'll be able to change their mind. They aren't even responding with rational arguments.