Hi,
awards of the Iron Cross stopped in 1925, HOWEVER, it was possible at a later date to get the medal itself if an award had been made and approved before the cut off date in 1925.
Most likely is that your guy had his award approved before 1925, at which time he was in Canada, then in the 1930s he wrote saying "Where is my bloody medal!"
I have a group where the gus has a note from the division in November 1918 saying "Lt XXX deserved the EK1, but the division has none to award"... fast forward to 1934, the Reichswehrministerium issues his award document and sends him a cross.
Best
Chris