Corlys damn near did it himself when Vaemond started talking spicy during the Stepstones battle
He made it very clear who his heir is, Uncle Breh not only spit on that but he disrespected the King and his kin to their face, even after Rhaenys warned him he would lose his tongue for such a thing
I don't see Seasnake changing his stance, he's riding that Strong boy (word to Aemond) to the Iron Throne and cementing a brehlaryon in that spot in the history books. His granddaughters being betrothed to produce the future heirs for the Iron Throne and Driftwood throne is the cherry on top if anything.
this makes a lot of sense
dap