No county officer, and no person employed by, or who is a relative or representative of, any county officer in the State of Illinois, while in office or holding office or while in such office or employment, shall have, possess or acquire any pecuniary interest, directly, indirectly or beneficially, or by any derivative process, in any real estate tax forfeiture or foreclosure in the county in which such county officer presides, other than the fee provided by law for the official duties of any such county officer in such proceedings. For purposes of this Section “relative” shall be defined as a spouse or child, or the spouse of a child, including a child by adoption.