I took everything, and for me, weed was the hardest thing to come off of surprisingly, it was the one I started on and the one consistent. Once I was able to go through days without smoking weed, that's when I really started to get better and didn't need the other ones. You need to get to the underlying cause, try and spend time with him everyday, positively, even if you do know he's smoking, don't bring it up, just try and keep every moment with him positive and try and build a relationship and trust, then slowly, try and bring up things casually, ask him why he takes it, then change the subject, if he's not being very 'giving' Give him time to reply and expand on how he's feeling. Try and talk to him openly about any problems you've had in the past, if you had any depression, anxiety, if you took any drugs at all. You need that connection for him to trust you, and to open up to you, then you can get to the root of the problems of why he's taking it and come up with a solution together of alternatives. Honestly, I wish my mum had done this with me, and now that me and my mum have got to that point in our relationship, I'm able to call her up and say 'hey, I'm having a bad day. I'd love to smoke or take ...' and she talks about why I want to do this, what I could do alternatively, and be a person to speak to. And I have been clean for years now, because I have that relationship. People take drugs to fill a gap in themselves. To make them happier, to make them less anxious, he's being defensive because he honestly thinks it helps. Give him a big hug and let him know how much you love him. That's all me and anyone else who took drugs and then went onto an addiction wanted. Love and support. Have a look at if they have a talking therapy service like time to talk, for future reference when you're able to get to the point of being able to talk about his anxiety and what you could do to help. But don't bring this up until he himself has brought up he has issues. Tread carefully, be positive and tell him how much you love him as much as you can x