I hope this isn't downvoted, but you should realize that quitting marijuana suddenly will make his stress far worse for 2-4 weeks. His real problem is some dee

I hope this isn't downvoted, but you should realize that quitting marijuana suddenly will make his stress far worse for 2-4 weeks. His real problem is some deeper misalignment with his emotions towards things. There's nothing bad about kanbans, they are tools used to help you get organized and get things done. There's also nothing bad about disagreements with your cofounder. The difficulty is that he's taking all of these things and reacting strongly to it. In all of my experience, I've never learned to teach this, but what he needs to learn is acceptance, and to live in the present. It's more important than ever to just give up control for a bit, let your cofounder do the leading. Taking on all the stress yourself is what kills you, and if you don't trust your cofounder, then you are taking on way more stress than you need.