DS school nurse advised the following for bedwetting:
Make sure they drink lots during the day (difficult during school days I know)
Avoid fizzy drinks even fizzy water
caffeinated drinks, e.g. cola and hot choc.
drinks with high levels of additives. If impossible to avoid these, only have earlier in the day. These all over-stimulate the bladder.
Avoid milk after teatime, and no drinks in quantity an hour before bed. If the child has drunk well during the day this will not cause dehydration. Aim for the last meal to be between 5 and 6pm. The aim of drinking a lot during the day helps the bladder to stretch to cope with larger volumes of urine, and hopefully hold more overnight.
On school days drink one large tumbler of liquid on waking, at breakfast, lunchtime, at least 1 pint after school and two tumblers with evening meal.
Non-school days, one large tumbler on waking, at breakfast, mid morning, lunch, mid afternoon, before and during evening meal.
These are minimum amounts, drink more if necessary.
Go to the toilet before going to bed, and again before going to sleep if there is a long time in between.
I hope this helps you all.