You child cannot control his bladder yet? This is a normal behavior until about 4-5 years old, after that, it may be an indication of something else, commonly a need of the child to remain in a “baby” state, often the need of the parents to just keep him on that state.
The wet bed can easily be transformed to a nice dry bed and the child can get full control over the function of his bladder with a short and enjoyable hypnosis. There are unlimited ways of achieving that, two of which are what I commonly use, depending of the age of the child and of course his personality.
Feel reassured about your child being hypnotized as, you know, children are very suggestible and are actually in a lighter or deeper trance state most of the time. Unfortunately, children usually go into a trance while they are watching cartoons, not the cartoons we used to watch, the modern ones, the ones with the violence and even sex and as they are in that state and thus very suggestible, any crap that is being said or being act imprints directly into their unconscious mind.
During hypnosis, usually a very short one, the child connects the feeling of a dry bed with a nice smiling state as to therefore look forward for a dry bed. And every time the child wakes up in the middle of the night or early in the morning to use the bathroom, he will get to get that sense of achievement which will put a nice big smile all over his face!