Its really hard to tell with that limited amount of information and lack of markings. Many nations, particularly South American ones (Along with China), adopted the Stahlhelm. As for M44, i take it thats a separate Spanish designation? Because German M1944's were never produced, and certainly never in the SCW.
He could make up som nice story though, saying it served with Spanish nationalists, and then with a soldier of the Azul Legion or something of the sort.