Grant remained involved with military life, serving in the Territorial Force until 1929, by which time he had reached the rank of lieutenant. He was discharged due to his age and also for being unable to attend camp. The same year he went to London to attend a formal dinner for VC recipients. He later worked in Paeroa but found it difficult to gain and maintain employment. By this time, his marriage had broken down and he had been made bankrupt. In 1934, his plight attracted the attention of the authorities. On investigation it was determined it was his own erratic behaviour that was the cause of his difficulties. Undiagnosed at the time, it is thought that Grant could have suffered from post-traumatic stress disorder.