 He was also a close confidant of Gen Jan Smuts and Winston Churchill.He was a member of the National Liberal Club.Graaff and his brother financed the building of the De Villiers Graaff High School in Villiersdorp in 1907, establishing a GB£100 000 (equivalent to £41,100,000 or R471,195,167 in 2010) endowment fund for the school.