GREY'S ANATOMY - "Sympathy for the Parents" - When Alex's younger brother, Aaron, shows up at Seattle Grace-Mercy West with a hernia, it's up to Alex to get Bailey's approval for his pro bono surgery. Matters are further complicated when Aaron discloses that his family has not heard from Alex since he arrived in Seattle, and parts of Alex's past long kept secret are revealed to his friends and fellow doctors, on "Grey's Anatomy," THURSDAY, APRIL 1 (9:00-10:01 p.m., ET) on the ABC Television Network. (ABC/RON TOM) JAMES PICKENS JR., PATRICK DEMPSEY, MICHAEL O'NEILL, CHYLER LEIGH, SARAH DREW