J.,
hi, my name is C., and i have 4 boys of my own. 15 yrs to 27 yrs. i just saw your request. i learned after having 2 brothers that did this until i have no idea how old they were, and watching my mom and dad do anything and everything, and then having my own boys that this is very often a hereditary issue, especially among boys. after my own boys were doing it, their dad's mom, told me their dad had the same problem, as well as his own father and brother. she said her dr told her it was hereditary. then i asked my mom, and she said the same thing, and that my dad also had the prob along with my 2 brothers.
as frustrating as i know it is, if it is a hereditary issue, there is absolutely nothing you can do but be patient. your little boy is prob emotionally frustrated, (or more) than you are physically/emotionally. making him feel like he has failed to do what he knows would make mommy and daddy happy might be killing him inside, no matter how hard he tries to not wet. try to be patient. with my first, i forget how old he was, but we had to go from diapers to those night time pants for bigger kids/people. unfortuantely, this might go on for years. hopefully for all of you, it won't. all mine quit at different ages. i have known other parents with the same issue, also. no medication, punishment, reward system, cutting back drinks, ect, will prob help. only time.
sorry i couldn't give you more hope, and my opinion is only one of many hopefully you have received. maybe someone else does have an idea, but from experience, i feel there is none, but patience, and tons of it!
good luck, and best wishes.
C.