When working with JJ and rote skills like multiplication facts, it is really important to give him plenty of visual models. Multiplication arrays are one such example. They lend themselves to easy connections to Geometry. We also play numerous games with dice and cards to add repetition without the drudgery of flashcards. When using flashcards, we always use color coded ones to anchor the math fact families.
There’s a great book called, Cloud Nine with wonderful ideas for helping make mathematically abstract ideas more concrete for greater retention.