I don’t know of a book recommendation, hope you get a good one. This op did make me think how our pastor has been helping us think a little differently about children and books/devotionals, vs. actually doing things with a parent and being actually trained. Not to disparage the idea of using a book alongside, that can be a great complement to training, but nothing can take the place of actually doing things with a father and hearing his valuable words as they are doing. Which you are probably already doing since you are taking this care with your son. But just wanted to toss out this idea since it has been so on my mind of late.