If he's been raising the issue for three years, I have to say that I would have hoped that by now we would be seeing a more intelligible question.
If all of the employees are now retired, they're not current employees.
If all of the employees at issue are current employees, then no one is "now retired".
If we're talking about a retirement deal that was negotiated and fully implemented three or more years ago, with no prior legal action or EEOC complaint, it's difficult to see how a present effort to make a legal claim would not be time-barred.

