he may have got out of france via St. Nazaire, and been involved in the Lancastria incident. The troopship Lancastria was bombed while anchored off St Nazaire on 17th June 1940 with the loss of an estimated 3000 (or more).
See another thread HMT Lancastria.
My dad was also in St Nazaire on that date, and he got back to Falmouth, presumably on the 18th June 1940.
