Doctor's advice is that until the age of 6 it is quite normal to wet the bed. Having said this, I have just helped my daughter to stop this. She is 4 and a half and was getting really annoyed that she wet the bed especially since her baby brother arrived. I found this worked
1. Limit drinks before bed. Lift him out of bed an hour after he goes to sleep and put him on the toilet for a wee, try turning the tap on to encourage him, then again in an hour or so then again before you go to bed.
2. if he wets the bed say nothing just change the sheets. if he has a dry bed tell him he's great.
3. tell him you used to do it when you were young and it will stop one day.
4. start a star chart with a star for a dry bed and a sad face for a wet one, five dry beds = an end of week treat, 7 dry beds = extra special treat BUT no punishment or comment must be made if the bed is wet and masses of praise when it's dry. Make the treats small but let him choose (we did bouncy balls, gingerbread men etc). encourage siblings to be kind about this not make fun.
Hope it works but if not go back to pull ups for a while, and make no comment. My daughter had to go back to them for a while. perhaps he's not ready yet?
CB100