Foreshadowing is easy why the trouble?
So many threads on this setting up parties etc, I posted this in the achievement thread but it seems to be getting ignored. You only need one other player when there is a brothers to the end event.
Split screen a spare controller each and in private chat search and research until you get paired. It took 3 attempts for me. The playlist has such low numbers it takes half hour to do this.
We tried for ages in parties with no success, this worked easily.