His brother, Charles Okey, said after Gurwood's death that his head wound had caused occasional fainting fits and that some eminent army surgeons had expressed the opinion that 'although he thought little of it, it might one day prove fatal to him.' Gurwood's friends attributed his ill health to over-work. In December 1838 Lord Hertford was 'convinced that your indisposition was caused by over mental fatigue' and urged his friend to come abroad and resume his old and pleasant life. Gurwood's final illness in the late autumn of 1845 manifested itself in chronic insomnia. On 28 November he wrote to a friend that the 'last volume and Index have upset me and I have been confined to my room with insomnia for ten days - not a wink of sleep!' On 15 December he said that the insomnia continued undiminished accompanied by fever. Fanny was almost as unwell as he from the constant attendance upon him.