The Unsaid (2001) on Netflix

Michael Hunter's lovely, beloved 17 year-old son Kyle committed suicide, although he was in therapy for depression. This ruins Michael's marriage, his daughter Shelly moves in with her mother. He stops treating patients in order to write and teach Psychotherapy, until many years later when a student gets him fascinated by the case of Thomas 'Tommy' Caffey. He was about to be released at his 18th birthday from the closed 'boys school' he was placed into after his father, Joseph, was put into jail for beating his adulterous mother to death. Michael feels that Tommy carries a big chip on his shoulder, ignores that Shelly fell for him at first sight, but is mesmerized by Tommy's resemblance (purposefully enhanced) to Kyle. There is also a revealing meeting with Tommy's dad in jail.