“but struggles to remember to write down his homework or memorize multiplication tables or simple formulas like area or a circle.”
Might I suggest you introduce him to computer programming? If he likes games, he might think it’s fun to design his own, and then he would need to learn the math in order to do that. Trick him into learning what he needs to learn, in order to learn what he wants to learn :)
Yuck I am a software engineer by trade and hate every minute of it.