Vic is pretty much identical to Vicky, except with a male voice, clothes, and haircut. Not much is known about him, or if he is related to Vicky's family in any way at all. All that is said about him is that he is Denzel Crocker's evil babysitter.
He looks like a boy version of Vicky, but it has not been stated whether or not he is a relative of Vicky.
When Timmy was exploring his crazy teacher Mr. Crocker's past, he learned that Denzel was once babysat by a sadistic babysitter much like Timmy is. Denzel's mother, Mrs. Crocker, was too busy to pay attention to her son, and left him under the cruelty of Vic, who is very similar in appearance to Vicky. His relationship to Vicky's family is unknown, as he was never explored more in anything other than name and job only.