Hardboiled Android
Vault Fossil
Of course, as far as I know there wouldn't be anything wrong with it. It was amazing work, and I would think he would want it to be continued to be shared.I was pretty inactive throughout the spring and just heard about Post. Incredibly sad news, I can't imagine how his family and those who knew him in real life must feel. Even here in a forum devoted purely to niche fans of a video game franchise you could tell he was an amazing person.
I have some of the campaign notes, about up to The Nursery I think. If by "Campaign Notes" you mean the gazetteer which lays out the various locations, their link to the main quest, and their associated side quests.
I can post it here or DM it if other members of the forum who knew Post better and worked more extensively with him on this project (like @Hardboiled Android) don't think it would be disrespectful.
But I actually think I have the full version. I've compiled everything I have from the project into a folder somewhere, I'll have to take a look.