ET looks back on the life of Brian Wilson as Hollywood mourns the legendary Beach Boy. A co-founder of the iconic group, Wilson is considered one of the most significant songwriters in American history. His personal ups and downs were well documented over the course of his decades-long career, his struggles with mental illness captured in the 2014 biopic ‘Love & Mercy.’ In addition to his musical legacy, Wilson leaves behind seven children, including Wilson Phillips members Carnie and Wendy.