"When making a portrait, my approach is quite the same as when I am portraying a rock. I do not wish to impose my personality upon the sitter, but, keeping myself open to receive reactions from his own special ego, record this with nothing added: except of course when I am working professionally, when money enters in,—then for a price, I become a liar..."
— Edward Weston, Daybooks, Vol. II, February 2, 1932
I'd put him between 35 and 45 - remember most people married and started spawning much younger than they do today, so it would be entirely possible for him to be 35 and have three teenage children. Whoever he is, it's not Hitler. This guy's jaw is too square, for one thing.