How to change font-family of all curly brackets and brackets?

I want to change only curly brackets’s and bracket’s font-family. How to do that?

That depends entirely on the grammar provided for a programming language. For example, it’s possible in JavaScript and CSS but not in PHP:

Example:

.syntax--brace.syntax--curly {
  font-family: "Times"
}

Since Atom is built upon Chromium, you can use the built-in inspector to find the class names.

Example: