Nah, Drew knows OF the methods, but not that they are being used on her family.
This next part is Drew confronting Hunter. If she was just lying to Sterling about knowing Hunter was drugging everyone, why would she go to Hunter to grill him on it.
I think that's enough evidence to suggest Drew doesn't approve of Hunters methods. Drew "wants" to use love and care to get the girls. Like we will probably see in Lucia's bad end. She was just drugged herself when she used the bottle on Brenna. She was under the influence of the gas in that scene.