It is apparently a tradition in Ghana for people to carry a coffin on their shoulders and dance in the street on their way to the burial site.
It makes a memey music video https://www.youtube.com/watch?v=j9V78UbdzWI
If you're referring to former Grassley aide Mike Davis, this is his tweet https://mobile.twitter.com/mrddmia/status/1307122198214258688
Someone else (blue check Jon Levine) claimed Grassley said he'd vote no, Davis refutes this.
EDIT: Also, some twitter rando added that Grassley said that back in 2018, subtext "times change"
His wife has connections to an oversees shipping company, where one of the boat crew was caught with cocaine. One year, Mitch's primary opponent used this in an attack ad, calling him Cocaine Mitch.
After winning the primary, Mitch's campaign tweeted back a picture of him photoshopped in a cloud of cocaine like the TV show Narcos, captioned "Thanks for playing"
Not a theory. It's just the answer to the other guy's question.