Yes, the alpha knew how to keep his people safe, but his son, on the other hand, did not. His son, Nathan, was foolish and believed that having fun was more important than people he was meant to protect. He was to take his father's place in two summers. He could not wait as he craved power and control. This would ultimately destroy everything his father created, but he did not care as long as he was on top.
The alpha believed that when he found his mate, she would straighten him out and help him become the alpha he was meant to be, but he foolishly destroyed his chances at that.
But this isn't his story. It's about the mate in which he rejected.