Is he in a spell cause why is he thinking differently from what he's saying

From the spoilers ive read Derrik is under heavy mind manipulation by Yvonne. That's why he's protecting her this much. Still doesn't justify an ounce of what he has done.

I agree with you! Apparently Derrick see Penelope as a woman rather than a sister which is ever more disturbing

Look closely... His eyes are glowing blue from Yivonne's spell. When he's spitting nonsense they are glowing and when he comes to his senses they are normal