Douglas was a dedicated Christian who regularly attended his local church, St Paul's Church, Boughton, a church he rebuilt. His house, Walmoor Hill, included an oratory. He also had a "strong sense of national loyalty", incorporating statues of Queen Victoria in niches at Walmoor Hill and in his buildings in St Werburgh Street, Chester. Douglas was not good at handling the financial matters of his practice. The Duke of Westminster's secretary wrote of him in 1884, "A good architect but a poor hand at accounts!". Delay in presenting his accounts often led to difficulties and confusion; such delay sometimes amounted to as much as ten years. Otherwise very little is known about his personal life. No family papers have survived and none of the documents from the office at 6 Abbey Square has been found.