Hello, I am Rafael. Thanks for asking your question - I'm here to support you. (Information posted here is not private or confidential but public).
I am very sorry to know about your situation.
A scenario like this uses to be very shocking for most parents, specially if there were not aware of child's drug abuse issue before this situation.
There is no alternative approach here but the need to be totally open and honest towards him about reality. To offer your support and affection but also to make it very clear the boundaries and limits he must respect, and the rules he needs to comply in order for him to receive any form of healthy support from you.
He would need to get into a drug rehabilitation program and start individual counseling right away, taking full responsibility of his choices and actions, from his rehabilitation to job.
Does it make sense?