That actually strikes me as quite a cogent argument! That cannabis is natural, and pharma drugs aren't.....
Maybe then (illegality apart!), it's a question of amount/duration/frequency, and that cannabis should be regarded by him as 'for emergencies only' or some such. It's good to hear that he can control the amount he uses......

The 'better off without him' argument is terrifying. I do appreciate that the thing we parents fear most is the loss of our children, and when that is 'self-administered' that is the most terrifying of all. I do hope that you are in contact with parents whose children are as vulnerable to that 'self-persuasion' as your poor boy is.

How do we convince someone that their loss from us would devastate beyond compare? Can other parents who were not able to stop their children from taking that most terrifying step of all, help to deter those still at risk?

It's great to hear that he can still 'turn outwards' and offer a helping hand to others ..... can this be expanded, do you think, especially in the direction of 'face to face' contact with those in need? I know this may sound trite, but working with animals, too, can be therapeutic in that they are 'simpler' to be around, and in that way can be restful to those humans with tormented and complicated souls.....helping animals is very, very direct, too, and usually quite immediate (cleaning, housing, petting, taking for walks, etc etc). It also doesn't need CRBs to complete, etc!)

I'll throw in one more 'helpful hint' (!!!!!!!!!!!!!!!!!) - how is your son when it comes to exercise? Exercise is another 'win-win' in general - it releases our feel-good hormones, endorphins, AND directly improves our health and appearance.

When your son is with you, does he help in the house at all? With my 'firm love' hat on (!), I do most strongly believe that realising that ALL OF US have to 'earn a living' is a very clear reality check. If he does not do paid work, and he is not volunteering to the equivalent of a normal day at work, then really he should be using at least some of that time to help in the house with chores and so on......

Again, sorry, sorry, sorry, if this is all so trite and obvious and 'helpful' in the way that only strangers giving advice can be (!), but you never know....bits may 'gel' and be of a small amount of use. Or easily discarded alas because none of them apply, or are already adopted.