What's the deal with this (fake?) chimney on my house?
Your dad is wrong. Chimneys have been used for non-fireplace heating systems since the days of the Franklin Stove.

Also, remember that the interior of the house may have been drastically rearranged over the years. My kitchen definitely isn't where it was when the place was built, and in fact the old kitchen space is now my dining room.

The only way to be sure what's going on is to get a look at the chimney itself, and see what kinds of openings may have existed and then been bricked up, or to research your house's history.