Luna (1979)
While touring in Italy, a recently widowed American opera singer has an incestuous relationship with her 15 year old son to help him overcome his heroin addiction
Alpha Dog (2006)
Johnny and his pals kidnap Jakes 15 year old brother Zach, then assign his buddy Frankie to be Zachs minder They develop a brotherly friendship Zach parties with his captors as things begin to spin out of control