According to Rae, their souls were replaced with ones which were absolutely loyal to him, right? But the system also said that they still had some affection to people close to him.
He wanted to see just how loyal they would be. If the two twisted brothers could not do it, he could just cover it up as a test, saying things like, 'This was a test by me to you, how could I expect you to remain loyal to me if you are not loyal to your own family?' And stuff like that.
He had actually examined Maxine with the personality scope when he entered the throne room. The reason for this was the strange look in Maxine's eyes.
He also shivered slightly when he smiled at him.
It felt suspicious to Harry, and thus he examined him with the personality scope, only to be dumbstruck due to his internal thoughts.
He was suspicious of his brothers and for some reason much more on guard of him. His loyalty dropped drastically from his previous 50 to 30.
