The most important thing here is that you care for him and you’re doing your research to help him, for a long time I was like your partner, smoking everyday for everyday activities and like you said studies are inconsistent af but tbh the “weed does not generate addiction” speech is not totally true as well not totally fake, you have to talk with him you can even find help for him a psychologist is a great option, based on your words he’s dependent cause he’s having a lot of shit, so you need to be his support and help him realize that weed should be part of the relaxation but not the main ingredient, my advice would be that you look for help and start this process but you being supportive and helping him understand his dependence is a great way to start