From what you’re written sounds like he just doesn’t seem interested. You’ve got to keep him interested and motivated to cooperate.
Ok first of all don’t make a big deal out of it if he still doesn’t get it..after explaining over and over.. and don’t show any frustration with him ever. It could be he’s convinced he simply cannot do it or it’s boring for him.
Learning should be fun regardless of how old the student is... and can only take place in an atmosphere, which is calm and relaxed.
As soon as he’s frustrated, bored, or lost interest move on to something else. Don’t keep pushing him to pay attention it’ll never work.
What works best with children is make a game out of it. You’ll be surprised how even the naughtiest kids will start paying attention and cooperating if its fun and suddenly they want to learn too.
You’ve got the right idea using manipulatives. The blocks or pretty much anything that can be counted can be used.
I’d find what he’s really into.. cars, Yuigio cards, action figures ..whatever..
You can play some kind so of game where you have to keep score and the award for doing something better or right is a card, toy whatever. This does not mean you got to go out and buy stuff to bribe him with use what he's got. In the end you have to count how many both of you have to see who won.
This should work cause he’ll want to know if he won or not.
What kinda game you could play?
Use your imagination ..!
You could play some board game. Almost all of them involve counting spaces.
Count the number of things of a particular color, shape, size or texture around you or outside. See who gets the most and even eventually have him keep score.
Have some kind of goal or use even a basket and count who gets the most balls or whatever into it ..
Often you’ll find you can teach kids a variety of different things at the same time without them even realizing they are learning anything useful at all.