Melody for Three

Melody for Three is a 1941 American film directed by Erle C. Kenton, one of the six films of the Dr. Christian series.
Plot summary.
Dr. Christian takes an interest in a young boy, a violin prodigy, whose mother is a divorced music teacher. His interest isn't just in the boy's music career—he believes it would be best for the boy to have his parents back together, and sets out to do just that.