It's lost on me why you would come to that conclusion. Okay then, whatever -- not the case, though.
Per your article that you posted --> "After he hit send, Short posted a screenshot of the email to Twitter, along with a text conversation with a family member who initially did not respond positively."
Note how it isn't wrote like this:
"The next day, Short posted a screenshot of the email to Twitter," or, "Some period of time later, Short posted a screenshot of the email to Twitter," or, or, or ...
No. It's as it's written, leading with: "After he hit send."
That should widely be accepted as soon after. It's insinuated as being so, at minimum.
The son simply couldn't wait to show his ass on Twitter which reasonably portrays him as being a narcissistic attention-whore.
Just on grounds of showering family affairs onto social media if it were my kid they'd already be walking on thin ice, let alone attempting to hold me emotionally hostage. Fuck that shit. This punk went on to further say he didn't want to "waste any more time on things that aren't bringing light to my life," so apparently being a drama queen gets them off. Furthermore, he said: "This letter was a boundary, not a persuasion. It was not intended to persuade anyone." That is an obvious lie. He's a manipulative sack of shit which is a trait narcissists have.