He doesn't have a BB gun!
I see. Then let me rephrase my question: Is the golf obsession harming any pursuit of his that is, or ought to be, more important to him than golf? That's where I would draw the line if I were a parent; from what you've written so far, I can't tell whether or not that's the case with Mo.
: From earlier discussions, I'm fairly certain that several posters in this thread are glad I'm not anyone's parent. Whether they're right or wrong is a separate issue. Still, you may want to keep this in mind if you're ever tempted to consider any parenting advice I give.
PS: If the root of your concern is that Mo's personality might be vulnerable to addiction, don't
try to change his personality. I don't think you can change it. What I think you can
do, though, is teach him how to act
on his personality. For example, you can teach him how to form and cultivate habits that are constructive, or at least non-self-destructive (like golf). You can also teach him how to tell if an addiction is taking over his life, how to think about his trigger-action-reward cycle, and how to manage it accordingly. Come to think about it, this is the kind of issue that school counsellors spend a lot of their time helping students with. So if you and Mo both trust "Ben" the counsellor, how about calling up "Ben" and talking it through with him?