To not let my 18yr old DS have his drugs back

If he has money in an ISA, can’t he use that to pay his debts?

I would consider telling him you will take him to rehab or turn him into the police. Since you got rid of the evidence it’s not a real threat though so I don’t know if it would work.

We live in Scotland, so the rules might be different. When we used the Police to help evict him, they took him to our local council offices. Intially he was placed in a council flat with occasional housing officer visits. He was then referred to a Young Person's supported housing project.
Supported housing varies according to where you live, your son's social worker will be aware of availability and his suitability.

I do hope that you have managed to get some support for your son, yourself & family.

I think you have to take this really really seriously. Give him an ultimatum it stops or he goes. I’ve seen how this plays out. YOUR home will be raided if he’s caught up in dealing. I’ve known a woman who had no idea her son was dealing and police had been following her for two years. Knew where she worked, knew what time she left the house every morning, knew her friends, knew absolutely everything and she had never noticed she was being watched. Son sentenced to 10 years. Chances are your son is on their radar already but they want everyone and they collect evidence until there’s enough to put everyone away. If you go to the police you risk your son but also your families safety if he’s involved with the supply of cocaine. That’s not me being dramatic it’s serious. I’ve known peoples houses to get raided and every adult in that house dragged out infront of their children. Instant social services involvement, schools are informed, if you have a respectable job that will be affected too. I’ve known of peoples houses getting petrol bombed for going to the police. This is not self medicating ADHD, this stuff ruins lives. This isn’t a bit of weed this is very dangerous stuff to be involved in and it’s an addictive buisness to be in because the money that is made is insane. That’s how so many young men are drawn into selling it. They always think they won’t do it for long just want to make a bit of money and then they’ll get out of it and what happens is the police are aware of everyone involved for a long time, they’ll plan to arrest some young boy in his car with a smallish amount and that gives them the go ahead and they get warrants for everyone and everyone’s doors go in all on the same day. And your son will end up with his photo on a big news story with 20 other people “drug gang jailed”. I don’t mean to be harsh here but do not allow your son to destroy your life. The police will not look at your son as a poor boy self medicating or someone who just needed some money they will come down hard and you will be powerless to stop it.

and let’s say that doesn’t happen, he doesn’t know what he’s selling. He could sell someone something that kills them. Your son then goes away for years. And please don’t think oh no things like that don’t go on in my area, I promise you they do.

Op have you identified what it is yet? I wouldnt flush it as you dont know if its been paid for, dealers wont think twice about doing him over or damaging your car/house.

Have you google lensed or chatgptd a pic of it.....

This sounds incredibly frightening and overwhelming, and understandably you’re feeling desperate. If you can, consider speaking with your GP for guidance on how to support your son while keeping your family safe.

This is really worrying and makes you really vulnerable. I do have quite a bit of experience with that