I like the 1952 Nash Rambler convertible, and what I think is the back of a Nash Healey behind the Mercedes. Did those Mercedes models have the odd combination horn & turn signal controls mounted in the center of the steering wheels? I remember one of my Uncles owning a Late 50's Mercedes 2-door sedan with that odd set up. I found this page from the 1959 owners manual
That seems to be a rather poor translation. The following claims to be a steering wheel from one of these. Back then, Mercedes was into safety research which was likely why the horn button was padded. As shown, European market models had a conventional stalk for actuating the turn signal lamps https://www.oldtimer24.com/2009/08/11/august-1959-mercedes-benz-bringt-die-sicherheitskarosserie/
It was a Late 1950's Model sedan that he owned that had the Horn Ring also control the turn signals, and it was shaped more like this. If I remember correctly. Its about all I remember from riding in that car. He didn't own it for long as he soon got tired of all the German car comments he received about it in the Midwest.
That would have been the best reason for keeping the car. They probably laughed at him for getting rid of it