Arad wasn't worried about his own power; in just a few years, he had grown far stronger than most beings. His growth speed was utterly terrifying, and he knew it, so in his mind, it made sense to make the others closer to him stronger.
At first, this might've seemed unreasonable, as he was the dragon supposed to protect his wives and family, but looking at it from another viewpoint, his reasoning became clear. In any position of power, whether it was being a king or a gang leader, having a family was always a glaring weakness.
Arad's enemies are smart, and they would rather target his weak wives rather than him personally, so Arad had to make sure his wives were strong enough to protect themselves. And it didn't just stop at his wives, he wanted everyone from the maids and servants, up to his own children and wives, to be powerful.
