"We try to focus on the joyful moments and memories," Robin's son Zak tells PEOPLE.
"We're still grieving," says Zak, 32, the oldest of Robin's three children. "We're moving through the process of healing and recovering," he says, noting that they've been aided by "wonderful family and friends."
Nearly a year after the Oscar-winning actor and comedian's death on August 11, 2014, Zak says he and siblings, Zelda, 25, and Cody, 23, are trying their best to celebrate their father's life and to honor him in whatever ways they can.
For Zak, a tech marketing executive, that has meant devoting time and energy to helping others, like his father did. Since October, Williams has been volunteering every week, teaching financial literacy to inmates at San Quentin State Prison, along with a current inmate, Curtis Carroll, who goes by the nickname Wall Street.
The class teaches practical skills including how to create a budget and how to responsibly handle personal finances. It also explains how the financial markets work, so that inmates can learn about investment strategies and how to save money, skills they can use in their life, inside and outside of prison.
About 50 students are currently enrolled in the nine-month program at the prison, he says, adding. "We have a wait list."
"As I go through the process of healing, working with inmates and focusing on the Financial Literacy Initiative and criminal justice reform has been healing for me," he says.