In a condolence message by his spokesman, Mr Femi Adesina, in Abuja, Buhari sympathised with Government and people of Rivers over the loss of the political stalwart, democrat and administrator.
Late Graham-Douglas served differently as Minister of Aviation, Minister of Labour and Productivity, and Minister of Tourism, leaving a legacy of distinguished service to the nation.
The president noted the historic roles Graham-Douglas played in entrenching democratic rule and a liberal culture, joining well meaning Nigerians and global leaders to stand and speak for justice and fairness.
He lauded him for promoting grassroots development among his people.
The president believed the investments of the departed in people and building of institutions will be remembered by posterity.
He prayed that the almighty God would grant his soul a peaceful rest and comfort his family.