Marshall Goldberg, 55, and his mother were found in Frazier Park.
Investigators said Doris Goldberg, 85, had been missing since May 24 from the house she shares with another adult son in Ashland, Ore.
Authorities said she has Alzheimer's disease.
Detectives believe Marshall Goldberg took the woman because of a custody dispute with his brother.
Sheriff's officials said Doris Goldberg was evaluated at a hospital, and arrangements have been made for her to return to Oregon.
The Associated Press contributed to this report.