Its pretty well documented, by very reliable sources about the origin of Cha Cha It was formulated by "front " men in latin bands. They often shuffled their feet forwards and backwards,( they still do ! ) during the slower Montunos and Guajiras creating a sound that was interpreted as Cha cha.. Onomatopea..
Jorrin, the musician, is given credit for the musical interpretation, which we now know as Cha cha. Its roots are in Danzon and Guajira .The B/room style was developed primarily by teachers in the states by the A. Murray studios (names, like Laure Haille, Barbara Paul and Bebe Black.. all are ex national d. directors from the 40/50s and 60s ( I worked with all 3 on different occasions )
As to Kellys brother. that's the funniest thing Ive heard in a long time !!