Hi M.,
Wow, you have given him an enema? my son had the same exact problem, most of the time I just didn't understand how someone could just not poop for so long. But after countless doctor visits they all said the same thing they said to you, he's fine, don't worry about it. So I didn't, and I still don't, he is 12 now and occassionally he has bowel problems, without going into to much detail, his poop is unusually large, I know gross. But other than the occassional toilet overflow, he is fine. I tried laxatives with him one or two times but it just didn't feel right, I never did an enema or used suppositories, I think one time he wanted to use a suppository because he really wanted to poop, but he didn't and he ended up going anyway. My advice to you would be listen to the doctor, the more pressure you put on your son to go to the bathroom, the more he won't. Just leave it alone and if he comes to you in pain because he hasn't pooped, give him some childrens pain reliever and explain to him that there is nothing else you can do. Also, another thing to consider is diet, what does he eat? does he get enough fiber? my son and I have gone the rounds on that one, he never eats veggies or fruit. I did discover early on though that he loves fruit juice and he will drink V-8 splash like its going out of style, he gets everything in one. Please write back if I can help anymore, and good luck.
J.