Movie Buffs

Does anyone know the name of a movie about an engineer who took a job in South America. While there, his son was kidnapped and raised by an indigenous tribe. Finally, the son was brought back to the States but could not adapt to modern life. My mother saw this movie in the 50’s she thinks (so, no, it’s not the recent film with Tim Allen). She says it’s a very sad movie. Can anyone help?

It sounds like The Emerald Forest, but that was in the 80’s.