Well I personally consume cannabis myself because it reduces my anxiety...perhaps he feels similarly. Not all regular users are addicts per say and if it doesn't hold him back from graduating college and its viable to move to a state its legal and get into the industry not sure I'd see it as such.

Though from what I hear just in general with addiction is someone sort of has to see some kind of downside to want to quit...but then it could still be very difficult. Also generally speaking a person probably wont not do something because others tell them not to if they see it as a positive. It is probably much safer than the alcohol would be, as far as toxicity though so if he isn't going to go entirely clean & sober at least cannabis can be a somewhat safer alternative to alcohol.