I guess what I'm trying to see is, should I just walk away and not get worked up or should I be the friend I promised to be and be there for him, push forward, go to his house, talk to him or his parents and let them know that now is the time to get this straight?
As honorable as all that sounds, it's not your job. You cannot push someone into recovery; they have to want it more than anything. If he is avoiding you, it is probably because he is using again. You are much better off to just stay away from him and take some time to get your own head back together. He has already stolen money and jewelry from you. If he is using again, it's pretty much guaranteed that he'll do it again.
You deserve much more than this guy is able to offer you. It's easier to cut your losses now than to hang in there for another year or more and be all that much more entangled.