Sounds like Joe had a favorite son and then a less than favorite son.
I suspect the favoritism started a generation earlier, at least. Joe was the designated standard-bearer for his generation and his siblings were expected to step aside or even indenture themselves to the favorite son. It reminds me of Joseph Kennedy Sr. and his designated standard-bearer Joseph Jr. JFK was the second string choice. (Which makes me wonder if this is an Irish thing to put the weight of the family on one child.)
At any rate, Joe’s siblings seem to me like the little guy in the Fractured Fairytales segment on the Rocky and Bullwinkle show, following the parade and cleaning up the poop. Then Beau was the designated standard-bearer for his generation and Hunter and Ashley were the James and Valerie to be his squires. Now that Beau is gone, there are no more unsullied standard-bearers and the family must face the future on their own as Joe totters closer to oblivion. That would make anyone bitter.
That’s obvious, all Joe talks about is Beau. He says Beau s/b President not him.