+1 for puzzle feeders to eat up some daily cat energy. I've had great success with these two: $10 silicone puzzle feeder (works for wet food), and specifically these $13 Mousin' Around Hide 'n Treats (for dry food or small treats.)

If he doesn't understand the Hide 'n Treats right away, start by leaving them out in obvious places, have some treats right around it, and even create a small trail of treats. Once he learns that batting it around = more food, gradually increase the difficulty of hiding spots. You can repurpose any old boxes that you were going to recycle for new hiding spots.