Regarding whether or not alcoholics express their true feelings while drunk:
When someone is drinking, their thoughts slow down to a crawl and usually get stuck on one thought or feeling. (think about the "I love you, man" drunk scenario).
This is why they get fixated on some issues and won't leave it alone. These thoughts/feelings sometimes have a tiny bit of reality behind them, but will come out all distorted and twisted up.
Just because someone says something while drunk, it doesn't mean that's how they feel.
Alcohol slows down a person's thinking to a crawl, removes their filter, and impairs their memory. The result is a mess of twisted up thoughts and feelings that they often don't even remember.
Sometimes, there is a grain of truth in what comes out when someone is drunk, but you've got to remember that it's likely magnified and distorted.
If you'd like to read a good book depicting the inside thoughts of a functional alcoholic, read The Good House by Ann Leary.
Here's a link to The Good House on Amazon: https://amzn.to/2nO6eZr
The Good House by Ann Leary on Amazon: https://amzn.to/2nO6eZr