My father was a alcoholic, who had long stretches of staying sober before always falling of the wagon again.

After he had been on a particularly long bender, which finally caused my mother to divorce him, me and him had a verbal fight where I decided I would not have more to do with him until he would seek the help we knew he needed (and we had been offering him for so long).

I'll add that he was a moody drunk, never abusive and when not drunk he was the sweetest person.

Some months later he fell badly while drunk, and hit his head. The resulting internal bleeding caused damage to his prefrontal cortex, which resulted in personality changes and loss of inhibition.

Within the year he had a heart attack, alone in his apartment, having ravaged his body with the lifestyle he lived.

I wish I had been less stubborn, more understanding, and would have helped him get through his illness at the time. But I was only in my early 20s at the time, with much left to learn.