What was the joke?
The ‘joke’ was a remark about his daughter leaving high school, leaving her dad (out of the house). Totally inappropriate at this moment, but that his typical.
“What was the joke?”
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He was talking about how peaceful and bright America is (obv. a sneaky swipe at Trump) where children are graduating and going off to college, then joke about his daughter going to college - something like “to their father’s dismay (or the like)” - chuckling - “I’m getting a little personal”.