Yes. Your post didn't at all surprise me. There are documented cases of such occurrences, though not all about becoming resistant to alcohol. Many years ago, for example, some guy who was suffering from severe bipolar depression accidentally shot himself in the head while cleaning his shotgun. He never suffered from mania or depression after the incident.
People have been known to lose their sense of smell and taste after fighting a virus or bacterial infection, and also after suffering a closed head injury, sometimes losing their taste for previously favored foods, and acquiring a taste for foods they never liked. Of course, there are many stories about dramatic personality changes following head injury as well.
I don't recall all the specifics, but many years ago I read about a guy who was suffering from Korsakoff syndrome (wet brain). He was a miserable drunk prior to the onset of the disease. After losing virtually his entire long-term memory, he appeared to be happy and well-adjusted emotionally. And he lost his desire to drink.
I worked with a neurologist for a few years, doing psychotherapy with his patients who had closed head injuries, including a physician with Dissociative Personality (or Identity) Disorder, aka, Multiple Personality Disorder, who was for a time doing rounds in a hospital while under the control of one of her alternate personalities. I witnessed tremendous mood swings in my patients, and dramatic shifts in personalities from pre-morbid to post-injury (typically based on reports from friends, families, partners, colleagues...).