Mom Pleads for Return of Son Who Vanished After Dad Passed Out in Park

"My son's disappearance is my worst nightmare," Ana Estevez said.

A California mother has issued a desperate plea: Please help me find my son.

Ana Estevez hasn't seen her little boy, Aramazd Andressian Jr., since he vanished while in the custody of his father. The dad was found passed out in a South Pasadena park Saturday, the same day the boy’s mother reported him missing.

Read: Missing Student Found Safe, Teacher Arrested After More Than a Month on the Run

“My son’s disappearance is my worst nightmare,” Estevez said at a press conference in downtown Los Angeles on Wednesday.

Estevez also reached out directly to her son with a message of hope and support.

"Be brave," Estevez said. "Mama and a lot of people are working hard to bring you home."

A reward for information that helps officials find the boy has been doubled to $20,000 by the Los Angeles County Board of Supervisors.

In April, Aramazd Andressian Sr. failed to show up to a prearranged meeting site to return the boy to his mother. The boy’s parents were in the middle of divorce proceedings and had been sharing custody of the child.

Estevez last saw her son during a Skype video call made from an undisclosed location, authorities said.

Andressian Sr. was found unconscious in a park and was taken by ambulance to a nearby hospital April 22.

Officers combed the park and surrounding areas, but found no trace of the boy. Andressian Sr. couldn’t remember how long his son had been missing, authorities said.

Read: Man Who Cracked Missing Student and Teacher Case Says Teen 'Looked Depressed'

Detectives said Wednesday that Andressian Sr. had taken prescription drugs the night he was found passed out, CBS LA reported.

In a statement released by his attorney, Andressian Sr. said, "I can only speculate that I must have been attacked in the park, given my unresponsive state and subsequent physical condition."

Watch: 6-Year-Old Girl Missing Since 2012 Found Dead: Cops