In 2011, 36 years after his retirement from parliament, it was reported that he had spent $16,000 on subsidised flights in the first six months of 2011, charging taxpayers for a total of 29 flights for himself and his family. Having lived for many years in the Adelaide eastern suburb of St Peters, he died at Calvary Wakefield Hospital, aged 95, on 10 August 2019. In 1977, Forbes was made a Companion of the Order of St Michael and St George in recognition of service to the parliament. He was awarded the Centenary Medal in 2001, "for service to the Commonwealth Parliament and as Chairman, Commonwealth Serum Laboratories".