What method was that? And I am on Xbox... so no console
The game platform doesn't matter.
When your companion and you lose each other, the companion
walks back home.
If they didn't get killed, they're headed home and it may take
several game days for them to get there. I don't know where that would be yet for each companion NPC in FONV atm. For ED-E, it would be the Express Station in Primm where you did the repair.
In FO3, sometimes I could find them by running along the route they would take on the way home if I didn't want to wait for them to get there. Remember, you can run; they don't run; they
walk it. And save your game if you do run after them. If you leave them alone, they'll make it safely back. But if you catch them and there are enemies around, your presence may get them killed.
That's the way it was in FO3.
B)