[Guardian]

near as I can tell the only way to be addicted to it chemically to the point of jonesing (becomeing irritable, aggressive, needy, etc), is for there to be serious instability already to the point that the THC and endorphins affect neuro-chemical imbalances so that you become dependent on it for that balance.

I mean, if it's the only way for him to feel stable and helps him control his issues, I say let him.