Robin Williams' son Zak opens up about his dad

Robin Williams' oldest son is opening up about coping with the loss of his father, four months after the actor's suicide.

"I miss him all the time," Zak Williams, 31, said in an new interview with People magazine.

He added, "Often I see something or if I'm watching a film, I think, 'Oh, man, he would have appreciated this' or 'He would have gotten a laugh out of this.'"

Zak, whose mother is Williams' first wife, Valerie Velardi, is the oldest of Williams' three children -- along with sister Zelda, 25, and brother Cody, 23. "There's not a day that goes by that we don't think about our dad," he said.

He added that he's found comfort in giving back. "It's through helping others that I've begun to heal," he said.

Williams died in August at the age of 63.