Yup, I'm actually isolating right now before a trip that's coming up that will be all people all the time, so it does happen.
However, not to be a downer, but I'd look into hotels in the area just in case, so if he doesn't show up you have somewhere to go. I'm not trying to scare you, but at least if you have an idea of where to go, you'll be prepared for the worst case scenario. (I also say this because I actually had that worst case scenario happen to me, although I was tacking on the visit to another trip, so I ended up just staying with a friend... and he started out all excited and planning, then dropped off, and then a military buddy died a few days before. I got a text in the airport while I was on my way there. And yes, it totally sucked, but I survived.)
And I agree with
@Solara, that you two should come up with some basics regarding communication and what is and what isn't acceptable. And, unfortunately, minimal communication may not be possible, which is a good indication that he's (sadly) not in the right place for a relationship right now. I'm sorry, I know it's not easy, but also know that it's not easy on either side of the fence, (both of which I've been on) as he's most likely feeling like crap about what his PTSD is doing to him.