Abdul (The Horses of Diomedes)

In the short story The Horses of Diomedes, Abdul is the servant of General Grant at Ashley Lodge in Mertonshire. When Poirot calls at the house, General Grant summons Abdul to bring a whisky and soda for his guest. Abdul wears a turban but considering that General Grant is a fake and never had been an Indian Army officer, it is not clear if Abdul is truly from India or just someone in disguise to lend "atmosphere" to the household.