He may have earned enough quarters to collect SS if he worked at all in the private sector.
Also, I believe some state and local government employees do participate in SS.
You need 22 quarters plus they average it over your working years. He would have had years and years of 0 contribution during his public employment.
I know that some public employees are now being put into social security rather a publicly funded pension. That happened with NASA and other government agencies a long time ago.