Treating nighttime bedwetting needs to be personalized. Unfortunately, we do not fully understand why each child wets his bed. It may be that his bladder is not yet fully developed to hold urine all night or, perhaps he may not always be able to recognize when his bladder is full. Sometimes having your son avoid drinking lots of liquids before bed, particularly those with caffeine, like soda or chocolate milk, can help. Also, be sure he always goes to the bathroom just before he goes to sleep. Waking up your child to urinate before you go to bed may also work, but getting up in the middle of the night is not usually successful, as you have already found out. I would also recommend using a rubber or plastic cover between the sheets and mattress to protect the bed from getting wet. Have your son help with the changing of the wet sheets. Of course, be sure to give him positive reinforcement on those nights when he is dry.
Your son's bedwetting can also be a frustration (and exhausting) for you and the family. The most important thing to realize as a parent is that your son does not have control over this "problem" and probably wants it to stop more than you do. It's not your fault, either; bedwetting generally doesn't have anything to do with how a child is taught to use the toilet.
If your child wets himself during the day, is uncomfortable while urinating, feels a burning sensation, or has cloudy, pink, or foul-smelling urine, speak with his pediatrician to be sure this is not a urine infection.