It's not selling cannabis, it's selling stocks in a cannabis company. So basically it sounds to me like a scam.
Either he'd be getting scammed, by paying the people his airfare and rent or whatever up front, or he'd be scamming people by selling stocks in a cannabis company.
I've recently heard of a cannabis company scam, someone sold shares in the company and there was no company , and no cannabis field or whatever. This was in the US and they were arrested, it was on an anti-mlm page. Can anyone shed any light on the details, that's all I can remember.