The son of Nancy and Ronald Reagan says he was inspired by his parents' unfailing devotion to each other during their 52-year marriage.

Ron Prescott Reagan spoke on NBC's "Today" show Monday, a day after the former first lady died in California at age 94.

He says his parents were inseparable, and that when they were apart, they talked on the phone every day. He says his father wrote Nancy endless love letters.

His older sister, Patti Davis, says her mother died peacefully in her sleep — just "how she wanted to go."

In a statement on her website, Davis thanked mourners for the outpouring of support she has received on social media.