Crean returned to his practice in Harley Street but by now his war service had begun to seriously affect his health and he was unable to maintain the business. Towards the end of his life Crean suffered from financial difficulties and in June 1922 he was declared bankrupt. He died from diabetes on 25 March 1923, aged 49, at his residence 13 Queen Street, Mayfair, London. He is buried in St Mary's Catholic Cemetery, Kensal Green, (Grave No. 896). His father, Michael Theobald Crean, is buried in the same cemetery but at a different plot.