Tolkien's letter seems to imply that the Sons hadn't made up their minds yet, but they arguably would have also been aware (being born in TA 130) that by Aragorn's day the 'choice must soon' be laid upon them -- referring to the time of Elrond's abiding.
Granted the Elvish perspective of years is different. But their Mother had already sailed, their sister chosen mortality, and 'now' their father was soon to sail -- but still no choice? If they were leaning towards immortality one would have thought this was a good time to leave Middle-earth, with their father.
Of course I'm not claiming that there is only one interpretation. One could argue the text could well mean 'with him' in the sense of choose immortality as he did, though at some later time. Letter 153 could well be the 'answer' despite what (I think) is suggested by other description.
I don't think any thread has ever solved this issue, and perhaps Tolkien would have wanted it that way.
|