Just because weed itself isn't physically addictive and won't cause withdrawals doesn't mean you can't be addicted to it. All addictions work the same way that if YOU let the addiction take over, then it will. Now, that being said, I can safely say your friend is addicted to weed. No matter how ridiculous and asinine that sounds, it's the truth. Slap some sense into this kid and make him realize that weed isn't all there is out there, and it certainly isn't the best and only thing worth mentioning. People like your friend are the reason why weed isn't legalized yet, because people are afraid of what weed could turn them into even though only a small percentage of even daily smokers turn out like your friend. Ask your friend what makes weed so great, why he does it, what makes it so important to him, etc...Maybe you'll get some sort of response as to why he feels the need to steal just to smoke. Perhaps he has some underlying reason (depression, anxiety...) why he smokes, and that's what's making him do all the things he's been doing. If you consider him a really good friend, he shouldn't have a problem telling you about what's going on.