Charlie Boy

What is the meaning of the euphemism: "Charlie boy?"
In a 1907 University of Nebraska yearbook, it was said of a graduating senior, "Roy Dwyer. He might be called a 'Charley Boy' or 'Mother's Pet,' if we did not know him." In the 1960s it was said of Roy, since deceases, that he had effeminate mannerisms. I am curious to learn whether the term "Charlie Boy" had particular meaning in 1907 culture and language. Can anyone help me with this? I'm wide open to insights to my grandfather.

There are several entries in various reference books for "Charley." It meant a man with a moustache from 1900-19 and, in the 1920s, an Army chaplain (as in Charlie Chaplin). It also can mean a generic name for a guy and a term for cocaine. No dates on those uses. In one reference there are two entries for charlie-boy. A soft or effeminate young man and to work as a busboy (as in Asian, Charlie Chan), 1974. Random House Historical Dictionary of American Slang, Volume 1, A-G by J.E. Lighter, Random House, New York, 1994. Page 380-381.

The connection to effeminacy could either originate or be reinforced in the popular stage-play "Charley's Aunt", first produced in London in 1892 and moving to Broadway the following year. It concerned a couple of Oxford undergraduates who needed a chaperone to keep a meeting with some girls, so they enlisted a friend to dress up as the titular Aunt.