You have done the right thing , you are not to blame – he will hopefully learn now that he shouldn’t buy drugs and pay later if he hasn’t the money.
If you had paid his debt he would of done it again and again and again and bled you dry.
Please be strong , he’s an adult and made the choice.
I Know it’s easy to say as he’s not my son but you know it’s true.
For his sake you had to say No .