Even though there is a consistent pattern of sons rebelling against fathers, it was not the absolute pattern. In this case, Heth received the throne as his right, but as with the later king Noah of the Zeniffites, he turned from God.
In such times, God is not silent, but sends warnings through his prophets. In this time, however, the prophets are rejected and they are cast out. As with the Nephites, this turn to wickedness after righteous blessings will lead to a fall.