>>96915130
With no TCG experience he may just need to find decks or cards he likes.
Don't even start with 'meta' decks if he can't grasp some more basic concepts.
Theres a reason the anime decks and structure ones are more 'basic' for children to actually understand.
Let him pick his own cards and realize basics then how lines can go, instead of throwing him an 'optimized' plan to memorize lines for instead of naturally learning gamestates.