Heavy drinking and alcoholism are complex issues. Confounded by the fact that alcohol is condoned and embedded by our Western culture
In the case of alcoholics repeated use can actually change the connections in the pre-frontal cortex part of the brain. And so rational thinking is diminished.
Most people operating in their rational brains know that excessive drinking alcohol is a bad thing. Even when it impacts their family life, work and their own health.
But the pleasure circuits in the brain may have become too strong to change without help and support.