Reddit mentions of Road of the King

In addition to the rulebook and youtube suggestions, reading this article series on interpreting the text of cards is important to avoid common points of confusion.

I was about your son's age when I first became hungry for more competition and began traveling to regional level tournaments. If you find that your son is reaching a similar point, then I recommend this bestseller, written by the co-founder and CEO of my company. It explains all the advanced foundation needed to win larger tournaments, and includes a lot of general principles that can extrapolate to success in any game or career.