I'm surprised the elders became spirits in the, relatively for a high elf, short period Aesir was away. I mean they're elders, so it made sense that they were due for becoming spirits, but it seems that it might have been accelerated by worry due to Aesir's sudden and surprising departure. No guilt from Aesir about that yet though.
With that said, who knows why they became spirits. Maybe after Aesir departed, their main concern was that he was another one of "those" special cases, and they decided it'd be better to dump all the responsibility for handling him to Salyx while chilling as spirits somewhere else. XD Well, it's probably not that; high elves are apparently special souls so there likely isn't a bad one amongst them, and they were genuinely concerned about Aesir.
I do wonder about Aesir ot crossing paths with the elder turned into spirits, but they may have decided it'd be best to not actually interact with him but to just get news of him via lesser spirits. He did leave without telling anyone so maybe they reasoned that it would be best to let him grow without obvious supervision.
230 years old? i feel somehow he is older than that or does he just pick that age randomly?
Well, he left the forest when he was about a hundred - that's when he got bored with it. He went out, met Kaeha in her twenties, watched her die, and now he's seen Kaeha's child as a granny. So if we assume they've both had long lives and lived to their eighties, it checks out. He's spent a couple of years at each stop, and it may seem that he's spent more, but he's still just within the first and second generation of the first humans he has met. Overall, he's only spent a bit more than half of his life outside of his home forest.