'Real Housewives of Atlanta' star Kim Zolciak ’s estranged husband, Kroy Biermann , is demanding sole custody of their four minor kids – claiming she has been out of the country for weeks, TMZ has learned.  According to court docs obtained by TMZ, Kroy asked a judge to immediately change the current joint custody arrangement. The former NFL star claimed that “the facts surrounding [Kim’s] misguided parenting of the children, lack thereof, and blatant mismanagement of basic parenting