C.V.
It's likely that daytime isn't really the problem. Nighttime enuresis, or bedwetting, is fairly common for boys...sometimes up until age 8 or 9. It has nothing to do with laziness and is very developmentally normal. Basically, his central nervous system has not yet developed the ability to signal him at night when he needs to go. There's not a thing you can do differently. Over time, he will develop and be able to hold his bladder no problem. Just be patient, have a good mattress cover, some protective pants or a pullup, extra sheets and clothes, and continue to encourage him to use the bathroom before bed.
My oldest had this problem until he was about 8. For awhile it was nearly every night. Over time it lessened and then it stopped completely. He just needed to grow a bit.