His reaction, upon hearing that his GF was no longer welcome to live there, with him, says all that can be said about his sense of entitlement. That he has not called to apologise says something, too.
This is not about drugs or GF's and all to do with maturity.
He's 28 and capable of sustaining himself. If not now, when?
You have given him a gift. May he one day appreciate your strength to do so.