It’s a different kind of scummy going on here; he didn’t want his grandkids to actually eat it, he wanted to get media attention and stoke more fear in his base. It would be like someone slipping razors into their own kids candy to rage-bait about Halloween being unsafe.

To be clear, this isn’t any better than the alternative; he put his grandkids in danger for a publicity stunt that could have very easily resulted in them consuming the drugs. Which also raises the question how how he got that cocaine in the first place.