I'm sorry Jo, it just stinks to be the parent of an addict.
With my son I learned to trust my instinct. If I thought he was using, he was. Time always proved what my heart already knew. The time came when I no longer felt the need to "prove" things lest I be called "crazy". I knew when I knew.
he left yelling and slamming the door, so Im sitting here now thinking - how do I handle it when he comes back.
When he comes back it might be a good time to set some serious boundaries and also to be truthful and tell him how you feel about the money.
I wish I had set and enforced boundaries long before I finally did.
However this unfolds for you, we're walking with you here.
Keeping you boy in my prayers.
Hugs