Bruce Davis, convicted with Manson and another man in two murders unrelated to the infamous Sharon Tate murders in 1969, is set for an appearance before a parole board panel on Thursday, the eve of his 70th birthday.
Davis had been set for a hearing earlier this year at the California Men's Colony at San Luis Obispo, but he became ill and it was delayed. He is imprisoned at the facility.
"It's time for him to go home," said Davis' attorney, Michael Beckman, who has been fighting for years to get his client released.
A parole board determined in 2010 that Davis was ready for release, but then-Gov. Arnold Schwarzenegger reversed the decision citing the heinous nature of the crimes.
Davis became a born-again Christian in prison and ministered to other inmates, married a woman he met through the prison ministry, and has a grown daughter. The couple recently divorced.
Beckman said Davis also earned a master's degree and a doctorate in philosophy of religion.
Davis has been in prison since 1972 after being convicted in the murders of musician Gary Hinman and stuntman Donald "Shorty" Shea.
Davis was convicted in 1972 along with Manson and another follower, Steve Grogan.
Beckman said his client is totally rehabilitated and meets state requirements for parole. Los Angeles County Deputy District Attorney Patrick Sequeira planned to oppose his release.
Few followers of the infamous Manson cult have been released from prison. Grogan was freed in 1985 after he led police to Shea's buried body.
Lynette "Squeaky" Fromme was released from federal prison in 2009 after serving time for the attempted assassination of President Gerald Ford.
Manson and two of his followers, Leslie Van Houten and Patricia Krenwinkel, remain in prison for life in the Tate killings. Their co-defendant, Susan Atkins, died of cancer behind bars in 2009.