Please explain to me how it is different that he and I occupy 21A and B, whereas I occupy say 2B and he occupies 21A.
I don't see any difference, same itin, originally on same PNR (and still linked). He has my EXP upgrade priority according to agents, so why not the ability to move to row 21 (he is in row 22 which is an elite zone as that is where we were before). I'm only asking to move him from one elite part to another.
I understand it's frustrating but it's the rule...once you're in a different cabin than your non-elite companion you can no longer select/change preferred seats for them. Whether the PNR is the same, linked, or totally different doesn't matter. As gemac said above the elite/non-elite seating perk is there so they can sit
next to you when you're flying together, not so they can have equal seating privileges if you're in a different cabin.
And getting annoyed and telling the agent she's not being helpful, when she's only stating the (correct) rule, probably didn't help your cause.
Hopefully your father's upgrade will clear and it will all be a non-issue.