The commitment to life long abstinence seems essential to recovery. I have never actually known an alcoholic who successfully learned to moderate. The Big Book says the steps are only suggestions. My best friend is 30 years sober, never went to a meeting, and probably could not tell you what Step One was. He just decided to quit drinking for good.
But I rather doubt that vowing to never drink again is a blank check that buys you the power to not have to do anything else. Recovery seems to be a bit more involved and other changes and perception shifts are often involved. While my friend looked like he just up and quit, my guess is that he processed a lot of thoughts and information without talking about it. But I don't know that, because... well, he never talked about it.
Meetings were helpful to me early on. The steps not so much, but as an adult, I do a lot of personal care taking that today seems to be fashionably referred to as "mindfulness," or taking inventory and making corrections. It's the kind of thing you would do with a counselor or therapist.
I guess a dry drunk is probably a person who is sober, but not happy about it. But I'm not going guess why he's not happy, or what it is that he might be doing wrong, if anything. It would be a tough place to be, however.