I can't tell if you're being sarcastic and don't believe him... Just to be sure, there have been multiple studies that support his claim (e.g. The Virginia Medical College 1974, Harvard 2007 and the Manual Guzman studies). The studies all show that: 1) Cannabinoids induce cell death, or apoptosis in malignant and unhealthy cells. 2) They also inhibit angiogenesis in said type of cells. That is, it cuts off the tumoral blood supply. So he is correct, cannabis has a lot of credit with treating cancer.