EU citizenship for my father?

I am a romanian citizen from a romanian mother and lebanese father. My mother and i have the EU pport, still my father didnt get the nationality. He studied and lived in Romania for a period of 10 years however that was during the communisme reign and rules were very strict at the time which prevented him from obtaining the romanian citinzenship. He's a medic and we are planning to move to Europe the next year. Please advise me on what to do and how to proceed. I've heared that there's a rule called family reunion under which my father should obtain the citizenship.. Please advise me ..