Well I think you have put your finger on it. 'Then I change my mind' could be my motto.
I am starting again after 11 months sober last year. I 'changed my mind' and drank again. But perhaps my mind was changed for me by the addiction. It seems we need every tool we can summon up to stop that happening. A positive attitude - i.e. seeing sobriety as an escape from a deadly trap rather than giving up a pleasure, one to one support, if it is available (that's what I am doing), and maybe group support. That usually means AA, though other brands are available.
Good luck to you friend.