"Flavio has signed a contract with Shabab to complete the move," Nader Shawki told FilGoal.com.
Angolan striker Flavio follows in the footsteps of coach Manuel Jose, who left Ahli to take over at Angola.
He seemingly sought a new challenge after enjoying four successful years with the Red Devils.
Flavio will play his last match with Ahli when they meet Angola's Santos on Sunday in the second leg of the Confederation Cup round of 16.
Zero to Hero
Flavio struggled to win over the fans in his early days at Ahli after joining from Angolan side Petro Atletico in 2005.
His first season with the six-time African champions was far from impressive as he managed to score just one goal - a fortunate strike against Ghazl Mahalla.
Fans and pundits started to question Jose's decision to bring in the 29-year-old, who seemed unsettled.
However, Flavio repaid Jose's faith in his abilities to go from zero to hero and become Ahli's main striker.
He finished the 2006/2007 season as the Egyptian league's top scorer and his decisive goals played a key role in helping Ahli win a host of local and continental titles.
He was also this season's joint top scorer with 12 goals along with Gaish striker Ernest Papa Arko
Flavio has been renowned for his ability to connect with pinpoint crosses from compatriot Gilberto and place deft headers into the net.