Instead of execution, can we give them terrible diarrhea? For the rest of their life?

I’d like to think that would be worse.

Blonde fella in a White House has that problem already.
Incontinence and diarrhea are very different things
They can be simultaneous.
so can blindness and deafness. they describe different functions.
Fecal incontinence. Urinary incontinence. They do, indeed, describe different things, but can be placed under the incontinence umbrella.
Diarrhea - Wikipedia

Urinary incontinence - Wikipedia