Hi N.,
I feel sorry for your boy. I was a bed wetter too, until I was 12 years old!! My oldest brother was 14 years old! My two younger brothers didn't have a problem. My Mother and her mother both wet the bed until they were about 12 years old also. One of my daughters also had problems, my other two children did not. It could be a heriditary factor.
A few years ago, I read up on it. I can't remember much but that it is a sleeping disorder.
I would consult a doctor if you are real concerned. Please, don't punish the boy or allow any teasing. He feels bad enough I am sure. Believe me, it is no fun waking up in a soaked bed! I was afraid that I'd be an adult & still do it...I was afraid I'd pee in bed with my future husband. That's never happened except one time when I was a young adult & real sick.
My Mom wouldn't allow us anything to drink after dinner...only monitored sips of water. She would also get us up a couple times a night. I don't think it helped any, it just made more work for her.
Good luck.