The real Sylvia kept her secret to all but a few family and friends. Remarkably, it was a Dutch public television producer named Arjan Vlakveld who found not only Sylvia, but also Sylvia's mother. Arjan told Songfacts: "The search for Sylvia was a big coincidence. I was having a glass of wine in the garden of my brother. He had quests and there was an American woman who after I explained what kind of things I produced, told me the story about Sylvia and her mother, who she knew. It was an old story because it was about her mother working on a high school with 'Sylvia's Mother.' She was already old in the time of her story. She didn't knew if it was true but the woman had claimed ones that she was the mother in the song. I only had a few names to go on and ended up in a telephone conversation with Sylvia Pandolfi, who at that time was a museum director in Mexico City. ('Down Galveston way' in the song meant in real life that she was getting married to a Mexican and moving there).
So I asked her the question: Are you by any chance the Sylvia in the song 'Sylvia's Mother?' She was very surprised because nobody knew, it was a personal and family story, she never told anyone. I filmed the interview with her mother in Homewood, Illinois. The same house where she had the telephone call with Shell Silverstein, probably even the same telephone number. She was 95 years at that time."
Here is the segment on Sylvia and her mother