Slim infirm? *Spoiler*

I see that Slim Pickens would live into the 1980s and appear in many films after this one, but he seems awfully gimpy here. I know he is pretending to be infirm, but he really does look old. Yet he was only in his mid fifties! Always loved Slim in everything, from Strangelove to Blazing Saddles. No one quite like him. He is one of many good things about this fine, underrated film.