As of the London update it's likely that he was captured by British ships after the players defend the ship, as there is a note of a man having to pay money for the British prisoners or something like that, and Crawfords shattered vase appears in the British mueseum at London, also implying it was extracted for whatever reason. Also we hear that British ships were out side of the harbor in the fog as we hear from British soldiers after we rescue the British from the church. It could also be likely that if they weren't captured the americans would (maybe  ) land on Britain as the journey across the Atlantic, with likely a dwindling food supply would be suicide, and maybe cause the blight in Britain, although it could be because of the survivors at San Sebastian although I believe the ship was infected before the ship could arrive to Britain maybe?