Hmmm, I've read that with enough exposure anyone can change their physical make-up in order to become an alcoholic. In the same way that anyone can get cancer if exposed to enough toxins. Some people are more resistant to the disease than others.
Who really cares?
I had a problem with alcohol, I don't have one today, if I started drinking again I would have a problem again pretty quickly. I think that could describe people anywhere north of 65+ in your scenario.