This might be it

[Latchkey]

I think in a way it's like digital hoarding and sorting and organizing. It's like the OCPD person that bins and stores things in neat little tupperware bins in a closet that make no sense (as to why) to anyone but them.

If the client did not ask for this email project and it is self-inflicted as it were then it does seem like more crazy-making and attention getting.
I work with someone who hoards both IRL and digitally. It's pretty awful on many levels. I mostly try to ignore it. The sad thing is that the digital hoarding does not = backup or backup plan as in the case of your PDH.  It's like, great, we have emails from 2002 on the old computer that is sitting on the shelf but if the modern database system we have running was to get struck by lightning the company would not have a way to get up and running tomorrow. This went on for years and years and has finally been remedied in my case. Still, it seems the lack of plan B is similar to my co-worker.

[11JB68]

 
Wow Latchkey, yes, exactly! Hoarding behavior for sure.
I truly believe h has ocpd!
A computer crashed about 5 or so years ago...2013 I think...since then he's been working on a self imposed project in which he is organizing his databases....or putting things into different databases I'm not sure. 5 years. This is what he does when not working on the client's stuff...but can't possibly take on another client.
Early on I questioned the usefulness of this and he got soooo upset and defensive.
On one hand I get that it's a defense mechanism and gives him a sense of control. But the time spent on these things is baffling to me.
He had me read some of his emails with client today. I don't get why the client is not yet wondering if something is not quite right here...I think most people would be running by now....but h's contributions to the project have been valuable, so I guess he doesn't want to lose that....

[Latchkey]

Speaking for myself, I tolerate the co-workers behavior because I can do my work around his behavior. The client may be buying time and sucking up to your H until they can find someone else. Or maybe they are just clueless. Also, I have found strangely enough, that PDs are often good at picking out other PDs and traits of those so your H's assessments of the client may be pretty accurate.

[11JB68]

I know we are not supposed to 'journal' here and hope that's not what I'm doing. This is an evolving issue so adding my thoughts. Thanks all for your feedback.
Yesterday updh seemed to have an epiphany about his client. I think todayhe is going to try to resolve stuff, it seems like booth of them want to continue working together.
Last night though he wanted my help/input...I've been trying to stay mc with him so this was a challenge, he pushed it So I obliged. Of course he argued with me almost right away...then accepted some of my advice, thanked me. Some of his complaints were about the client being cranky and yelling at him. It was late When we finished, then he asked me if we couldwatch a tv show. I said, well is pretty late...to which he let out a (growl/yell?)... I said what was that? He said frustration because I want to watch a show and clear my head before trying to go to sleep. (But really, the yelling is unnecessary!) Also he said, anyway it's Friday. I responded it's not Friday its Thursday. Him: well tomorrow is Friday. (???? I stopped jadeing...how is that relevant?) So of course we watched a show... I feel like he just shouldn't bother asking me. He apologized later, justifying that it's a stressful situation for him. I just nodded, since oneof my boundaries is that I do not say oh it's ok because it's not. As he's talking about the client He complains that the client doesn't see the irony. Yet HE does not see the irony that his complaints about the client are similar to my complaints about him.

[Latchkey]

It's not journaling, just a situation that is evolving. At some point this crisis will be over but your H just seems to be milking the attention for all it's worth. He has just one main client. I can't imagine if he had several.
Hang in there!

[11JB68]

So more weirdness around a meeting with the client.... Including my suggestion that he met with client in his own turf at our house/his home office, rather than at clients office. He did. A day or two later, uPDh comments that it was good he had the meeting at his own office, not at clients. NO acknowledgement that this was MY idea... Did he forget? Is he gaslighting? Lying (to me and/or to himself)? Testing to see if I'll correct him? In medium chill fashion I just observed and let it go... Weird though...

[Latchkey]

Did he say it was his idea or did he just not acknowledge your idea?
I'm so used to that with co-workers that I don't even notice. Have you ever read the book "I don't have to Make everything all better" by the Lundbergs ? It might be something to get and read as it has helped me so much in life and dealing with PDs and kids (as a parent) especially.