I've done the final mission in his quest chain five times in the past few days now.
I skipped through the dialogue the first few times, apparently that can cause bugs! Annoying but ok, sure, I can wait.
Go back a few more times, wait for the dialogue to fully play out and don't skip anything.
Still just stands there with his gun.
Like, I left years ago and am just coming back and have been generally having a great time on a fresh character, but holy shit it feels like the bugs and technical jank have gotten worse over the years I was gone, not better.
This isn't even the only quest I've run into this issue with at the last leg, after you've spend 5-15 minutes doing everything leading up to it. Just makes what would otherwise be a fun experience so frustrating and annoying.