Getting back to "My Brother Sylvest'," the earliest reference I've found is in The Morning Oregonian (Portland), Sept. 28, 1908, p.8. Sung in a comedy called "Coming through the Rye," it is described as a "more or less well known...dainty little Dago ditty."

The magazine Our Navy (September, 1915), p. 42, mentions "Brother Sylvest'" as one of several "Famous Italians" along with "Chris Columbus...Garabaldi...Marconi."

Sorry, no lyrics.