I would think that decarboxylate it first would make them more potent even though he didn't say. I decarb everything I eat and rub on my body.
With sugar the hotter you cook it, the harder it becomes this is the only thing that makes a difference between chewy candy and rock hard candy so how long to cook it for isn't as important as how hot to cook the sugar too. A candy thermometer is key to brings it to 275f, killing the heat and adds the kief mix only long enough to mix it then pours it out to cool. I'm not sure if during the cooling process it stays hot enough long enough to fully activate? decarbing would be my only suggestion
Hope this helps.