That's a tough one.
I know many prescribe to the don't veto / let it happen with trades unless it's obvious collusion. I don't think this is. I think Carter for Ekeler straight up would be, but in this case, the green horn thinks he's getting 2 starting RBs for 1 whose under performed (in his mind). It's a bad read and a bad trade, but I think it's honest.
With that said, I also prescribe to the notion that fair trades have one player getting no more than 30% extra value on a trade value chart. There are many out there, but this is my favorite (he posts a new updated thread each Wednesday):
https://www.reddit.com/r/fantasyfoot...rts_week_2_te/
This trade breaks my personal rule that I think everyone should follow. Since it's not obvious collusion, I would abstain from voting but share your trade chart of preference with the player (or on the team message board) and encourage more careful consideration in the future.