Hi Allyb
It must have come as a shock to you. Most of us have seen the tell tale sign of substance abuse in our sons/daughters. Never having any money, bad debts, loss of interest in hobbies, different friends, bit unkempt, change of attitude usually a bad one!
Its so difficult , as you see your child making all these bad choices and because they’re adults, you can’t really stop them.
Maybe he is just starting out, he might be able to stop it. He needs ti admit he has a problem first, and seek help on this forum or CA or NA meetings online or face to face where possible.
Read the other threads here, there is so much support and advice from others. I think he needs to be frank with you, addicts are such good liars and manipulators.
Hopefully he wil see sense and seek help, it has to be his decision though. Then you can support him as best you can.
Hope this helps. Take care and try not to worry, look after yourself.
Lx