Who is Grady (Grade A) Allison from Chasing the Dime: A Novel and what is their importance?

Grady is forty six years old and partnered with William Wentz in the on line sex trade. He has been arrested four times, most times including charges of great bodily injury and his photo makes him look older than he is. He has gray black hair that he wears greased back on his head and his complexion is pale. His nose appears to have been broken several times.