Hi Rina....people use drugs for a lot of reasons. Mostly to kill an emotional pain. When I first started using it was for fun, recreational use as they say.....then it turned into a way for me, and many others, to kill some kind of emotional pain that I could not then or now identify. Your man needs some kind of therapy that goes to the heart of his internal pain which he probably can't identify. He, probably like me, didn't know why he wanted to be stoned but after the fun use of hash wears off and I wanted to be stoned 24/7, isolated, with a bottle, I came to believe I needed outside help.
I found a good therapist and she helped immensly. It's killing the pain w/out drugs that cures the addiction. I wish you well.