It's a shame the OP hasn't had chance to return to comment on our responses.
Hello carandrog. Your situation seems very harsh, although I doubt the primary motive of the employer was to minimise the scheme's pension costs.
I'm puzzled by what you say about redundancy. If it was a genuine redundancy then I hope that redundancy payment was made (although judging by the size of the pension maybe he hadn't been there long). But I don't understand the bit about transferring him to another department so they could advertise his job- that suggests it wasn't a redundancy. If he was being transferred then he would still have been an employee wouldn't he?
Did you ever get anything in writing saying his role had been terminated? Firms do sometimes terminate employment on grounds of capability in these situations but only after a careful process, and notice pay should have been paid.
Maybe you should contact the company now, even though may be a few years later, and ask them to clarify and explain what happened.