There is NO SUCH THING as night time potty training. That is like saying you can regulate your blood pressure at any time while you are sound asleep.
If you use the search option on the top of this page you will find that this topic is asked about on nearly every page of mamapedia questions. There will be a multitude of answers all saying the same thing.
The brain regulates the production of urine.
Kids aren't supposed to wake up to go potty during the night. They are supposed to be like grownups and their brain is supposed to stop urine production when a person falls asleep. It is totally a brain issue. Not a choice, not a manageable thing a person can do at all.
One day the brain will kick in on this developmental stage and they will start staying dry. They will not get there any sooner no matter what you do.
If he is wetting out of his pull up then try a better pull up. We used the night time Huggies with Buzz Lightyear and Woody on them and they worked very well. We are not using Goodnites due to sizing but they are not near as good.
With my daughter I put huge depend pads inside her pull ups. It was years ago though. They are better now.
A full bladder is more likely to wake someone up. Drinking less fluids is more likely to make them dehydrated and more inclined to UTI's. It also makes them more irritable because it's just uncomfortable being thirsty.
I think if you want to regulate their drinking then let them have tons of water before dinner then just 8oz. or so between dinner and bedtime. But I really think it does not matter as far as the peeing goes. It just makes less for the pull up to hold....