J.L.
well it makes sense. If he just had a big pee before he got up then he naturally won't have to go for a while. NOt like he is holding it per say but just that there is nothing to pee out. Make sense?
After he wakes up is he drinking a lot? I don't know if my now almost 5 year old "got it" but when we started potty training she did not want to drink anything. I was like, how is this going to work then???? If that is an issue you can do what I did. I made popcicles out of that propel flavored water. Everytime she went potty she got a popcicle. It kept the juices flowing. ;0) It was the perfect reward because it was something she loved, it help with the process itself and it was instant gratification (plus there is almost no sugar in propel so I wasn't creating a hyper child. And it is colorless so it doesnt stain).
As far as a UTI, it is very difficult for boys/men to get them. It can happen but it is less comon. The urethra in a boy is at least 4 or 5 inches and in a man more like 10-12. Women get them so often because ours is only about one inch so it is more troublesome. Good luck. I think you are on the right track.