getting an animal sick?

Question
Can you give a water dragon phnumonia ?

Answer
Pneumonia isn't one I've found on any reverse zoonosis lists. What that means is a human infecting a reptile. That does not mean that certain viruses can't affect your dragon.
If you are asking this because your dragon is having a discharge or other respiratory problems, then I suggest getting him to a vet asap as infections of that sort can be deadly to reptiles.