My parents work ethics are very early 1900's. Be positive, be consructive, be thankful, never say anything negative, always do 110%, be humble in every situation, no mater what happens.
I get a small satisfaction, when I tell my father that I refused a promotion, because the position was a bullshit and a trashcan of unpleasantness, or that I resigned because the workplace atmosphere was not healthy. His face is always worth it.
Early 1900s doesn't mean 1900-1909. It usually means the early century (1900-1950). If they were born in 1945 then had a child when they were 30, that child would be 50.
Also, they might just mean that their mentality is like that of the early 1900s, not that their parents are necessarily that old.