If your wife has worked their for 27 years, she must have some former bosses or managers that she is friendly with and has good work relation. Cannot she talk to one of them to seek some advice. Maybe that person could make a call or talk to someone to figure out what is really going on. I know in a similar situation that I did just that and got some really good feedback from my former manager on what was going on with a new manager that i had just got and was having issues with. Did your wife talk to your boss's boss or above him. If you wife's boss is on a PIP and performing poorly, he might be saying negative things about your wife to upper management to try and save his/her own job. She needs a direct line to higher up in the organization.
And as was mentioned, your wife should be looking for emails and other documents to provide back-up to her position as to why the PIP is incorrect. She should also be demanding specific documentation of poor performance and not except general statements. The harder she makes it on HR and the company, the longer she will last (allowing time for a new job) and the greater the severance package they might give her to go away.
From the information given, I would bet the reason the company is ejecting her (and maybe her boss also) is a cost cutting exercise. When a large company needs to bring down the payroll, easier to get rid of a couple of higher priced employees (usually the longer you have been around the higher your salary) then getting rid of multiple new people as the new people pay is substantially lower.
Agree...but she is in a protected class due to her age. It is no different than being gay, disabled or an african-american. If they cannot justify letting her go versus somebody younger who is similarly employed, they are open to an age-discrimination lawsuit.
If I were her, I'd take the 90 days to document my performance and see if inequities persist. Then, I'd have an attorney write them a letter the day she is terminated. A good example is to show that the terms of the PIP were unattainable, provide evidence that other PIP's (for other people) were ever attained, and if they were attained, where those people retained.
In the end, embarrassment is more powerful than the lawsuit. The big value of the lawsuit is to gain discovery. Once gained, you can depose executives with affairs, breaking non-disclosure agreements, being asked to defraud a customer.....and so on. If you can show some of that, they will settle the week before the trial.
In my case, my boss hired a guy and gave him the fruits of all of my hard work. A month before I was fired, I found out she and he were having an affair when she replied to his email, with me cc-ed, telling him he couldn't come to her room that night because she had work to do. I then found emails where she had distributed confidential information from a prior employer (who was also a competitor). They went through every email I made for three years and reviewed my expense reports with a fine tooth comb. I also found evidence that they were postponing certain happenings to time them for release to shareholders to maximize their impact. Finally, I had evidence to believe that the guy in charge of the division was gaming things to maximize his bonus. This is not illegal, and not grounds for a lawsuit, but would have been an eye opener to shareholders that may have felt they were "gamed" into believing things that weren't quite correct. This is confidential but when it goes to trial, becomes public knowledge and that is where your power lies.
In the end, three working days before my trial, I got a call from my lawyer saying that there had been a "significant shift" from my former employer. They totally collapsed and made me a large offer to settle. I asked for a little more to shove the knife into the CEO's ribs just a bit more as a warning that he can't take his eyes off his employees or pay the price himself. I respect the CEO, who would still be friend with today, if not for this. But I wanted to send a message that you can't treat people that way and be bullet proof. Soon or later, some a-hole like me will take a stand. While the terms of the agreement were confidential, I bought a new car and posted it on my social media (again, to irk those involved). Now, a couple of years later, I've been contacted by many former emplyees for advice and to thank me for taking a stand.
Watch the series "Goliath" as I believe this pretty true (without all the drinking, sex and mafia type scenarios....just to the point of how you do the case and try to drive a wedge between the company and their insurance company).
If you are confident in your position, take a stand. File a lawsuit. It is unnerving but, in the end, will have results.