If people have to go to rehab because they smoke pot, I would've lived my life in rehab. This is going to destroy his pro-career, poor Ty!
Don't be naïve. Just because the substance itself isn't "addictive" doesn't mean the effects that you feel aren't addictive. Different people handle different things in life in different ways. Not only does he have this drug issue, but as someone else has already said he has a lot of personal issues that he might need to work out. Also, going to rehab get him out of the lifestyle that he is been in and away from the people that have drug him down.