PRIVATE PRACTICE - "The Hardest Part" - When Pete's brother, Adam (Kyle Secor), brings their sick mother (Louise Fletcher) for a consult, Pete discovers her illness may be his brother's fault. Meanwhile, in the wake of her book's success, Violets walks in on Sheldon just as he's about to take her archenemy on a date, and Cooper treats a young musical prodigy whose brain tumor could prevent him from ever playing the piano again, on "Private Practice," THURSDAY, MARCH 31 (10:01-11:00 p.m., ET) on the ABC Television Network. (ABC/ADAM TAYLOR) ALLIE TRIM, ANNE MARIE HOWARD, LIZABETH ALLEN, VANESSA MARANO, LAURA SLADE WIGGINS, AMY BRENNEMAN, BRIAN BENBEN