His eldest son, Ryder, died at the age of 23 on October 27, 2013, in a car collision, when he was hit by two cars after his car broke down on the Glendale Freeway. Ryder was a singer and songwriter performing in his band Ryder Buck and the Breakers, and was recovering from a year-long battle with a Stage 4 testicular cancer. On March 2, 2014, upon accepting the Academy Award for Best Animated Feature for co-directing Frozen at the 86th Academy Awards, Buck dedicated the award to Ryder.
