Ok so the lummox either gets himself stuck in the pedestrian part of the bridge or falls into the river both of which prevent progressing? How do I keep his sorry shiny metal @$$ going forward?

Sometimes he gets stuck for me as well, usually on one of the portable covers that the Enclave uses along the bridge. Reload a save. I make a hard save right before I walk out the door, into the sunlight. Sometimes I can get him to become unstuck if I advance ahead of him. He gets stuck for me, maybe 25 % of the time. Frustrating, right? Reload a save.

Yea just keep reloading.

I had him get stuck on the force fields a few times.

I also read that going too far infront can cause him to bug out.

That's probably the cause I got ahead to try keeping the rest alive.

Sometimes you can get him unstuck by running ahead of him and engaging the next group of Enclave soldiers. He *should* start moving again to come to your rescue. Sometimes he will advance, kill them and then stubbornly stomp back to the point where he was stuck again at which point the only thing you can do is reload your last save. It's always such a relief when I can get through that mission without any of those hangups.