Disagree that events A, B, C, and D must be disclosed to the PTO. So far we have no facts that suggest actual public use. Instead, all we know is that we don't know whether or not the invention was used in public.
That said, many practitioners would decide to play itself and disclose those events.
He contacted 5 to 7 (depending on who made the prototypes) companies. I would bet one of them spilled the beans to some degree. It's better to assume they all did at this stage than to find out post-issuance. You could ask them, but they might lie, especially if they've filed their own patent app on the idea. I agree with you in principle, though.
Plus, if any of the company peeps told him (a) it's been done before, (b) it'll never work and I'm an expert, or (c) we sold something like that 10 years ago and it sucked, then that triggers a particularly nasty version of the Rule 56 duty as well.
I'll just respectfully disagree that such is our job. We don't really help anyone by presupposing prior art that isn't known to really be prior art.
Well, if we assume none of it is prior art, then we may face rejections on previous disclosures or publicly available derivative work by others. That'll cost him $. If we assume all of it is prior art, then he may get a relatively narrow claim issued. In the former scenario, you end up implicitly over-promising and the client becomes increasingly unhappy with the lack of progress to issuance. In the latter scenario, costs are low, issuance is faster, and his most recent embodiment is protected.
Shooting for the perfect broad claim is not going to satisfy a client like this. Plus, he may not be telling you the whole story regarding past disclosure, especially as these ones are so old. Memory fades.
If any of the previous embodiments were commercially viable, then one of these 5-7 companies would be selling it by now, and then it would almost certainly be prior art under 102(b).
If he doesn't like it, he can find someone else. He's not going to like paying for all the research his 11 years of procrastination caused. He's going to be very difficult to make happy, unless he agrees that E-D-C-B-A is good enough.
There are too many known unknowns and most of them are unknowable under a limited budget.
"There are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns – the ones we don't know we don't know." - Donald Rumsfeld