Even if the coral did tell jokes, I wouldn't quit.

[He's that stubborn. Besides, nothing wrong with adding color to his language. He lacks it everywhere else.]

It's more than belief; it's the fact that there's hardly anything else that could explain it, barring extreme head injury or completely off-base delusions. Still it's the curse that's most likely. You're physically older already; a mental effect isn't that much of a stretch.