It's food for thought, Rita, and I wouldn't feel creepy asking it.
I'm probably the wrong person to answer as I am not a syphilis expert nor have I researched Curly's medical records, but I would not be surprised if I were to find out Curly did have something other than a stroke. I'll put it to you this way, I'd believe a man in his early 40's in general has a better chance of contracting an STD as opposed to having a stroke, though of course the latter is still possible.
That said, stroke is the official line, and unless if some research comes out that says otherwise, I'll stick with stroke. What also needs to be said is I've yet to read those links you posted below, so let me get to that. Good to see you Rita.