Bonjour Gary !

To say "He was a drunk.", you will actually use:
"C'était un ivrogne."

Have a look at our related lesson:
https://french.kwiziq.com/revision/grammar/when-to-use-cest-or-il-est-elle-est-to-say-it-is">https://french.kwiziq.com/revision/grammar/when-to-use-cest-or-il-est-elle-est-to-say-it-is">https://french.kwiziq.com/revision/grammar/when-to-use-cest-or-il-est-elle-est-to-say-it-is">https://french.kwiziq.com/revision/grammar/when-to-use-cest-or-il-est-elle-est-to-say-it-is

I hope that's helpful!
À bientôt !