You're a very kind and sweet person to want him to stop suffering. Perhaps I should be more like you.
But I want Nick to reach the point where the amount of alcohol he needs to drink to get drunk is so much that he gets unpleasant stomach/liver pains. And so he can't get fully drunk. And so he remains aware of what he said, and it's gnawing at him.
And then he starts getting the symptoms he can't ignore anymore and he decides to clean up. Get sober. But the more sober he gets the more he realises what he has done to John, to his family, to his parents.
If he keeps drinking, he will be in pain. If he will get sober, he will suffer psychological pain.
So he reverts back to drinking, secretly. But he spirals. And his family leaves him. And he hates himself everyday for what he's done. And his body hurts so much. And everyone gave up on him long time. And now he's living in a gutter and people are disgusted by him. And he gets on fentanyl, hoping he will just die.
But then everytime he overdoses, some kind EMT brings him back to life up. They lock him up in rehab for a bit, so that he gets sober. So that he once again remembers what a piece of shit he was to everyone.
And it goes on over and over and over until he's like 90 and one day he sees his grandchildren, all grown up and youthful and happy. They don't even want to look at him, for he became a gutter man by now.
And it breaks his heart. And this trauma clears his demented mind one more time so that one more time he goes through the epiphany and realises what a dumbfuck he was.
I wish Nick to live a long life, heartfelt.