Wetting the bed is usually nothing to be concerned about and is sometimes just a normal part of childhood and growing up.
I wet the bed until I was 15 years old. Bed wetting in my case was just a weak bladder that wasn't growing as fast as the rest of my body.
Most kids will eventually outgrow bed wetting and a good thing to do is have them wear pull ups or even youth diapers.
I wish I would have had some youth diapers to wear when I was bed wetting because I wouldn't have had to wake up in a soaked cold uncomfortable bed.