To describe your own (previous) condition as 'denial' is not unreasonable. To describe someone else's condition as 'denial' is to put yourself into their head.
I don't think it's a useful term, and it is worth emphasizing that not all recovery programs use it. Many of us had not recognized the impact alcohol was having on our lives--obviously quitting drinking makes many things clearer, especially hindsight. Perhaps our thoughts about what we drink 'for' are not entirely 'rational'. But describing someone else as delusional dismisses their perspective as being totally without validity.
We drink/drank for complicated reasons. Sometimes the way someone expresses something ('I have to get drunk before I can go home,' etc.) is another way of describing things that can be discussed as stress factors, triggers, etc.
In a behavioral approach we would look at those comments and explore them, because they indicate beliefs that may be leading to unhealthy behavior. Change the beliefs, you can change the behavior. So rather than calling them delusional, we'd ask if they are realistic, or exaggerated, or are based on absolute or demanding thinking.
Don S