Same here, no where to be found.
I think it bugged out the first time cause I was in a group.
There was an NPC (with a side quest) who I couldn't approach cause he was behind a locked part.
After leaving the group, most of the settlement unlocked (cause my progression was further) after which I was able to get the side mission.
But unfortunately, Henry isn't there anymore.
Even joining another group didn't work
Also stuck here. Henry is nowhere to be found. No markers, no character model... Nothing. I did freeplay matchmaking to see if anything changed. Henry did actually spawn at the administration table but I wasn't able to interact with him at all, or the container door like someone else mentioned. Leaving the party after didn't help, Henry once again disappeared. This is frustrating and appears to only be happening to a select few which isn't good newsThis is the only thread I've found about it.