L.G.
Try talking with your pediatrician and ruling out any medical reason. I KNOW it's easy to assume he is being lazy and just not taking time to go to the restroom but you never know. I had to see a urologist as a kid (not the same issue you are experiencing but had a bladder issue nonetheless).
Hoping it's not medical, your pediatrician is well versed on these issues and can provide some help/advice.
My daughter wet her bed til 7, she couldn't help it and grew out of it, same thing with my niece.
If he can't control it, you can understand that you wouldn't want him to be ashamed of himself for something he can't control. You know your son best so it's hard to tell if he is just being a bit lazy about taking care of his business or if he really can't control it. Sometimes childrens bladders are not "up to speed" with the rest of their body. Very normal.