"Just say no"?
Sadly, it doesn't work. If you're an addict, you'll end up manifesting in one way, or many ways. Drugs aren't the only way that it expresses itself.
I hate alcohol. I always have. The taste makes me sick. The best way to ruin a dessert, is to pour expensive booze on it.
That didn't stop me from becoming a prize-winning lush, though.
The thing about addiction, is that it just doesn't make sense. It can't be understood, when looked at, through a rational lens.
That's a big reason that Recovery is difficult. It's also often badly supported by family members, who don't understand the mechanisms.
But that's a long story, for other venues. I am happy to read his story, and sincerely wish him luck.