I always first made sure they drink enough water, add fiber to the diet, cut down on processed and constipating foods, give prune juice, soaked prunes, kiwi’s, no banana ! Also make sure your child moves enough. Another easy one is belly massages, clockwise around the belly button

Sprinkle unprocessed bran on his foods. He won’t be able to taste it but it will really help with the constipation.

Increase water and fibre intake and try kiwi fruit as well.

Is he having lots of water also? I find prune juice works well, or puréed prunes or whole prunes. Olive oil is good too, try drizzling over his meals