He's easygoing.

He's laid-back.

   Similar expressions   

 ◈ 그는 아무 근심 없이 살아.

    ▶  Nothing bothers him.

 ◈그는 도통 스트레스를 받지 않아.

   ▶ He never stresses out.

  Dialog  

A: I told Brian about the stock market

crash, but he just smiled it away.

B: Nothing bothers him.  He's laid-back.