i'm a recovering addict, and i agree with the card gesture. relapse is so common and the fact that he is living in sober houses makes the difference to me. i'm glad that he is doing so well and you and him have a lot to celebrate, but its sort of easier to live in a controlled enviroment and stay sober. the real test comes when he is out and there is no one to monitor his actions. i think rather that spend money on an expensive gift right now, maybe a bit too soon, unless you just have the money like that.
its true that it maybe a miracle for him but addicts sometimes celebrate those milestones by using, then how would you feel. i pray that he keeps going and that you continur to stay strong.