Technically speaking, if they're aware he has a legit mental illness like being schitzo they shouldn't be selling weed to him and i'm sure there is some legal technicality in there somewhere saying they can't, for the simple fact its well known that schitzos can have severe reactions to it because of their abnormal brain chemistry. That said, if by chance it ever did set him off and he harmed someone as a result I can see it leading to a legal shitshow when the victim found out they sold drugs to someone they had to know had clear mental issues, even if they didn't know what specifically. Its one of those things that falls well into the the whole legal 'may lead to reasonably foreseeable incidents' territory
Not that I expect him to go off like that as a result of smoking weed. At least not in his current mental state. Granted you never really know what might happen with people like lucas. He absolutely shouldn't be anywhere near it and they shouldn't be selling to someone who is clearly fucked in the head. But if he ever does it could certainly lead to questions being asked about the necessity of having an explicit legal requirement for not selling such products to mentally ill people in the name of public safety. Even if lucas never goes psycho cause of it who says someone else won't at some point
Ehh they don't really need to know his medical information to recognize him as being mentally ill. Given the product they sell has known potentially very serious side effects for people with abnormal brain chemistry its their legal responsibility to be aware of what they are selling and to who. Pharmacists can get in serious legal shit for giving opiates to people who are showing signs of being a junkie even with a prescription, gun store owners can get in even bigger shit for selling guns to people who later go off and shoot a bunch of people when it gets out that they were showing signs of questionable behavior in the store and you can bet if a liquor store sold booze to some guy with yellowing eyes and skin and it ended up killing him shortly after, the family would sue for selling him booze when they should have recognized obvious signs of liver failure, given the nature of their business.
Point being, nothing good will come to a business selling mind altering substances to someone with blatantly obvious mental health problems, and as a business its their responsibility to know who they are not supposed to be selling to. Its one of the reasons i'd never even consider getting into that particular business. That entire business is a liability lawsuit waiting to happen. Too much is sketchy about it legally speaking and its only a matter of time before somebody gets high from a something one of these places sells them, gets in an accident that kills a bunch of kids and claims there was something wrong with whatever they gave him. By the same token, selling anything to somebody like lucas - hell especially someone like lucas is a bad situation waiting to happen for everybody involved