Arwen Evenstar remained also, and she said farewell to her brethren. None saw her last meeting with Elrond her father, for they went up into the hills and there spoke long together, and bitter was their parting that should endure beyond the ends of the world.

This passage, and a comment by /u/removed_bymoderator in another post, got me wondering: how did Elrond and Elros get along after the War of Wrath?

Elrond's words towards Arwen sound fairly harsh, and understandably. This is someone who's lost so much over his long life. I could see him and Elros having a similarly bitter exchange after the latter chooses to be judged as a man.

For context: Elrond had lost his birth parents, his foster parents, his entire homeland, probably many friends, and seen unspeakable death and destruction over the War of Wrath. His brother was the one person he'd had throughout all of that. And now his brother was voluntarily choosing to leave him. How could he not resent something like that? Even with thousands of years of further life experience by the time of LotR, his farewell to his daughter is a bitter one.

Elrond sailed west fairly soon afterwards, though. Elros ruled Numenor for another ~400 years. That's a long time for hearts to thaw.

Did Elrond ever visit his brother, especially towards the end of Elros' life? It's established that the Numenoreans didn't visit Middle-Earth for a long time after relocating to their island. Nothing is said about whether ME's elves visited Numenor.

Another fun fact: it's not until 32 years after the War of Wrath that the Edain sail west for Numenor. Did Elrond and Elros have any contact during that time?

That's one of the fun (or frustrating, or both) things about Legendarium. There are so many unanswered questions and what-ifs to speculate endlessly on.