L.M.
I have to second Lillym. I was having this issue with my son and I'd get him up right before I went to bed, hold on to him walking to the bathroom, put him on the potty tell him to go (he did) then walk him back to bed. I did this truthfully until he got too big for me to handle, but by then he had grown out of it. I always felt better going to bed knowing he was comfortable.
My son is now 6 and had a very rare accident a few nights ago. He said he was dreaming he had to go to the bathroom and he woke up wet. hehe. He cleaned it up himself by putting a towel over the wet spot and going back to bed. Didn't even tell me - I only found out in the morning. Boys!
Good luck!