Actually, he's correct. It is still illegal under federal law, but states are "legalizing" it anyway. That's why banks will not do business with known "legal" growers. The ATF may, at any time, charge banks and growers, distributors with a drug crime if they ever decide to get some balls.
Back to the overdoses. Trump hinted at a cure. Go right to the source, and make it a capital crime with execution, and he references Singapore, a clean, nearly crime-free country day and night, that executes traffickers. Amazing...they have a miniscule amount of drug trafficking. (s).