You could watch the Jolson movie biographies very closely, and come away with the idea that Al Jolson was an only child. That was far from the truth.
Since they began in show business together, a rivalry of some sort existed between the Brothers Jolson. Nonetheless, after the death of his baby brother, Harry Jolson released a recording given to him by his brother back in 1938, "Du Host A Liebes Punim," and backed it with a eulogy to his brother, Al.