Is "Congratulations" an appropriate sentiment if someone is retiring?

Granted, my feelings are more along the lines of "good riddance" than "congratulations", but I can fake some politeness.
Anyway, BMR is retiring, as in he's packing up his things and will be gone sometime next week.
I suspect things will get worse before they get better, but my general mood can be summed up as Holy Crap (as previously stated, the man has no shame, so I really didn't think he'd give in: L thinks it might have reached the point of Retire Or You're Fired, though obviously they can't say it like that).